Let’s talk for a moment about the two-year walkabout that Novak Djokovic went on from Wimbledon 2016 through the French Open 2018. It happened right after he had pulled off the greatest men’s tennis feat of the last 50 years, winning four grand slam titles in a row. He had beaten Roger Federer at Wimbledon and the U.S. Open; he had beaten Andy Murray at the Australian and the French. Djokovic had 12 major championships before he turned 30. It was a remarkable career.

And then something — or multiple things — snapped inside him. It didn’t happen all at once. First he was taken out at Wimbledon by an affable American with a big serve named Sam Querrey. Then he was hit off the court at the Olympics in Rio by Juan Martin del Potro in some of the most thrilling tennis I’ve ever seen. Shortly after that, he was batted around by his old friend and foil Stan Wawrinka in the U.S. Open final.

Then, there were injuries, personal issues, motivational problems, who really knows everything that was happening? Djokovic doesn’t like talking about it except to say that he went through a lot. His entire 2017 was a train wreck, and he dropped out of the Top 10. His 2018, started off just as badly and he dropped out of the Top 20.

Worse, he often looked lifeless on the court, like he was going through the motions, which is the exact opposite of what peak Djokovic represented. There was none of that familiar screaming at his coaches when something went wrong, no barbaric yawps when he held things together and won a big point, no sense that he had any great reason for being out there.

Then he turned 31 and it was fair to ask if he would ever again find that reason. He’d spent a career chasing but, realistically, what was left to chase? By then, Federer already had 20 grand slam titles — eight ahead of Novak — and Nadal was right behind Fed, and what chance did Djokovic at his age and as the No. 22 player in the world have of catching them? Up to that point, the most grand slams any player had won after age 31 was Ken Rosewall with four … and that was a different time.

He’d already done so well. He’d made so much money. He’d fulfilled every dream of a scared boy who spent so many nights in the basement below his grandfather’s apartment while bombs exploded all-around his war-torn Serbia. It seemed like the perfect time to simply say: Well done.

And that’s when Novak Djokovic, for the second time in his career, transformed himself.

In many ways, this year’s Wimbledon was the first tournament that Novak Djokovic had all to himself. He has spent a long career being the other guy, the hunter, the upstart trying to intrude on Roger Federer’s dominance, the player trying to outslug the ultimate slugger Rafael Nadal, the unsentimental chap looking to knock out Andy Murray in front of adoring England at Wimbledon.

But this time, the stage was cleared for him. Nadal decided to skip the tournament to “prolong my career and continue doing what makes me happy.” Andy Murray did play but at age 34 — one week older than Djokovic — he is now ranked 102nd in the world and after a couple of sentimental victories he was unsentimentally dismissed by Denis Shopovalov. And yes, the seemingly ageless Roger Federer played at 39, and champion that he is he kept finding ways to win early. But no one is truly ageless, and he ran out of steam in the quarterfinal against a sturdy Polish player named Herbert Hurkacz.

Other top players — Dominic Thiem, Milos Raonic, Djokovic’s old pal Stan Wawrinka — pulled out because of injuries.

And so this was Djokovic’s tournament, completely, utterly, so much so that early in the fortnight the folks at ESPN held an informal poll for their analysts: If forced to choose a winner, would they pick Djokovic or pick the field. This is the ultimate tribute, the sort of thing that golf analysts used to ask about Tiger Woods when he was at his best: Tiger or the field? Now, it was Djokovic or the field.

A surprising number of the analysts chose the field. I call that surprising even though the bet they were making — that Djokovic could have an off-day — was certainly sensible enough. Tennis players do have off-days, particularly on unpredictable grass courts. The world’s No. 4 player Stephanos Tsitsipas, who had Djokovic down two sets in Paris, succumbed to American Francis Tiafoe in the very first round. The world’s No. 2 Danil Medvedev fell apart late in his fourth-round match against the tenacious Hurkacz. “When you’re No. 2 in the world,” Medvedev said in a pained voice afterward, “losing in the fourth round is a really bad result.”

Yes, off-days happen to even the best. And I would argue that Djokovic is not immune; not only that I think he DID have an off-day at this Wimbledon, a couple of them, in fact. He was pretty seriously off his game in the third round against American veteran Denis Kudla. He was absolutely outplayed in the semifinal against Shapovolov.

But he won both of those matches in straight sets anyway.

He won those matches and the other four leading up to the final because Djokovic has taken his game to a place that boggles the mind. You probably know the story of young Djokovic transforming himself from a talented but mercurial enigma into the No. 1 player in the world in 2011. It has been told many times, the way he changed his diet, the mental exercises he would put himself through, his near-fanatical focus on flexibility over almost everything else. Over the next six years:

— He won five Australian Opens

— He won a French Open and lost three times in the final, twice to Nadal.

— He won three Wimbledons, beating Federer twice and Nadal once in the finals.

— He won two U.S. Opens, losing three times in final.

This was the relentless Djokovic, known for his superhuman reflexes, his awe-inspiring return of serve, his unmatched speed around the court, his ability to go into God mode, where he simply would refuse to miss.

People think that today’s Djokovic is just an older version of that Djokovic … but he isn’t. There was that second transformation, the one after his two-year walkabout, the one that too many people seem to have missed. This version of Novak Djokovic plays the game with incredible variety and imagination and creativity. His game is almost never called beautiful — that’s Federer territory — but over the last three years, Djokovic’s game has reached new levels of beauty. He has painstakingly turned himself into one of the best volleyers in the world. He is probably the best lobber in the world (his combination drop shot-lob is now one of the most devastating and wonderful weapons in tennis). His slice backhand, particularly on grass, has become Federesque. His ability to not only chase down dropshots but hit unthinkable angled winners on them is second to none.

“He has no weaknesses,” John McEnroe gushes, and it is true. He’s great from the baseline and at the net. His first and second serve are both devastating, and his service return is unmatched. Djokovic these days brings an oversized toolbox with him into every match, and he can pick and choose which is the right tool for the job.

Throw all that in with his still unmatched return of serve, his uncanny ability to predict an opponent’s decisions, his stunning talent for rising above his nerves on the big points, and the good fortune that just seems to walk with the legends, and you see why he is immune to off days. The Shapovolov match is a perfect example. Djokovic readily admitted that he was outplayed. But not when it mattered. Denis had 11 break point chances — one more than Djokovic — but Novak saved 10 of them. Shapovolov was serving for the first set when he made two backhand errors; then he was the shakier of the two in the tiebreaker. Shapovolov had Djokovic down 0-40 on his serve in the second set, but Novak found a way to wriggle free. Shapovolov would talk about having chance after chance, and he did, but Djokovic shut them all down.

“He was a little bit more experienced,” Shapo said glumly afterward, “and just played probably better, maybe a little bit lucky — you know, more luckier than me today — in the bigger moments and that was it.”

I didn’t see calling Djokovic luckier was a slight or bad form from Shapovolov; Djokovic WAS luckier. He flailed at some shots that floated uncontrollably but ended up hitting the back of the line. He hit a couple of shots that Shapo was sure were out but on challenge review turned out to be in by the slightest of margins. Lucky? Sure.

But, as they say at the beginning of the movie The Color of Money: “For some players, luck itself is an art.”

Djokovic did show some uncharacteristic nerves in the Wimbledon final against Italian Mateo Berrettini, but you could hardly blame him for that. Djokovic is not only aware of the tennis history he is trying to make, he is shockingly open about it. He has been talking about winning the golden slam — all four majors and the Olympic title — ever since he beat Nadal at the French Open. He has been saying for years now that he wants to finish his career with the most grand slam titles. He used to have the number 310 written on his shoes — that was Roger Fedrerer’s record for most weeks at No. 1. Djokovic now owns that record too.

Athletes are rarely so openly ambitious. They usually retreat into perfectly logical statements like, “That is something I will think about after I retire,” or, “I hope to someday be able to look back and reflect but for now I’m focused on taking it day by day.” Not Djokovic. He comes for greatest ever. And he knew exactly what his match against Berrettini meant; knew exactly what a victory would mean:

— Victory would give him 20 grand slams, tying him with Federer and Nadal.

— Victory would make him the first player since Rod Laver more than 50 years ago to win the first three grand slam tournaments in a year.

— Victory would give him six Wimbledon titles, moving him past Bjorn Borg, putting him in the grass stratosphere with Federer and Pete Sampras.

And so, yes, he started out shaky, double faulting twice in his opening game, failing to serve out the first set, losing a tiebreak, failing to serve out the second set, etc. He was, once again, in the midst of an off-day.

But he knew it wouldn’t last. And it didn’t. He found his rhythm and once he nullified Berrettini’s massive serve — something that even critics admit Djokovic does better than anyone ever — the match was his. The final three sets were not exactly straightforward, but there wasn’t much doubt about them either. Djokovic won the final point when Berrettini sliced a backhand into the top of the net, and then Djokovic fell on his back and stared at the sky and let the cheers wash over him.

And, immediately, the greatest of all time arguments recharged because something vital had changed. The easy arguments that Federer and Nadal once had — hey, they have more majors than him! — was now gone.

So now, the arguments against Djokovic will become more subtle and personal, they will be about how he is beating up on a weak field or how he was an underachiever until Federer began to age out or how Nadal bettered him so often on clay or something else. And it’s a shame that the argument for any one of these incredible players must feature attacks on the other two. I’ve said it before: All three of them are the greatest ever. There has never been a player as breathtakingly gorgeous as Federer from 2004-2007 and he has endured. There has never been a fighter like Nadal, particularly on his beloved clay but really on any and every surface.

And, yes, there has never been a chameleon like Novak Djokovic, who can become whatever player he needs to become to rise to the moment. He will go to the Olympics, now, then he will go the U.S. Open to try and complete the first men’s grand slam since Laver eons ago, and once again the good folks at ESPN will ask: Djokovic or the field?

The bigger question is: Who can beat him?