NEW YORK -- It's a strange thing to say about a man who was playing for his third Grand Slam title of the year, but top-ranked Novak Djokovic's season has gone sideways since he won his first French Open in the beginning of June. The mystery of what exactly has happened to the Serbian star just keeps getting more curious.
In the space of two months, Djokovic has gone from being the surest bet to win Grand Slam tournaments the past two years to an enigma who crashed out of the third round at Wimbledon in July and bombed out of the Rio Olympics in August with an opening-round loss to Juan Martin del Potro that left the world No. 1 weeping as he walked off the court.
Then he seemed oddly subdued for long stretches Sunday during his four-set loss to Stan Wawrinka in the final of the US Open. And the crowd sensed it, too. It began chanting Djokvoic's name without prompting a handful of times, imploring him to rage back into this match.
"You know, in matches like this, if you don't use the opportunities, the other guy comes and takes it," Djokovic said.
Djokovic knows that's particularly true of Wawrinka, who has won 11 straight finals he has played. The other day, Djokovic didn't dispute an Italian reporter's teasing contention that "You are responsible for creating the Stanimal," a reference to their fourth-round 2013 Australian Open match in which Djokovic won the deciding set 12-10. The match gave Wawrinka the belief he could actually beat the world's best.
You couldn't blame Djokovic if he had flashbacks to that day or his 2015 French Open final loss to Wawrinka every time the Swiss hit a rope down the alleys.
But even if you countenance the idea Wawrinka, who has now beaten Djokovic along the way to all three of his career Slam titles since 2014, has somehow crawled a little inside Djokovic's head, that still doesn't fully explain Djokovic's current fugue state.
For whatever reason -- be it the unspecified "personal" problems he alluded to at Wimbledon or the more recent wrist and shoulder injuries -- Djokovic hasn't looked himself since June.
He has somehow transformed from a chest-thumping man whose reputation for fighting, scratching and clawing his way to wins no matter how long it takes to a man who endured Wawrinka's 6-7 (1), 6-4, 7-5, 6-3 march to the title Sunday rather quietly.
Along the way, Djokovic controversially resorted to the ploy of calling out a trainer twice in the final set. (It wasn't the first time he has been accused of bending the rules when struggling in a big match.)
Wawrinka was about to serve at 3-1, up two sets to one, when Djokovic requested the first trainer's visit not long after he'd spent a changeover icing both of his thighs. But when the trainer arrived, Djokovic took off both shoes and treated everyone to some adventures in podiatry by requesting treatment on -- wait -- his feet?
"The toenails were off and bleeding," Djokovic explained. "It was quite painful to move around. The toe just happened today."
Wawrinka was caught on TV microphones during the first six-minute delay complaining to the chair umpire that Djokovic was trying to buy time because he was cramping -- something that a player cannot receive treatment for during a match.
And Djokovic admitted in his news conference that he does know that rule.
But he denied under repeated questioning that he did anything untoward as a last-ditch ploy to win. And Wawrinka, who was only just three games from victory by then anyway, refused after the match to criticize his longtime friend and sometime practice partner for requesting the trainer's visits.
"For me, I just asked the umpire because he asked [for] the physio when he was serving, and we played maybe seven more points," Wawrinka said. "If your opponent is struggling, if he has blood coming out [of his toes], you have to stop."
As it turned out, neither pause had much impact on the match. Long before his feet began to trouble him, Djokovic's biggest problem Sunday -- besides the bombs Wawrinka was hitting down the lines again and again -- was he couldn't break Wawrinka's serve. And he didn't hurt Wawrinka much with his own.
Djokovic is considered the best returner in tennis history. But against Wawrinka, he converted only three of the 17 opportunities.
"It was a terrible conversion of the break points -- just terrible," he said. "I lost my nerves in very important moments today."
And so Djokovic moves on down the road now lugging a personal record of 12-9 in Grand Slam finals with him. He had won four straight majors until his early-round loss at Wimbledon.
A glass half-full person would rightly say it's an extraordinary achievement the 29-year-old Djokovic has even made 21 major finals. But Sunday, Djokovic -- who fell to 2-for-7 in US Open title matches alone -- wasn't feeling that way just yet.
"Obviously, Grand Slam finals are different than any other match, [and] I have lost a few Grand Slam finals, some close matches," Djokovic said. "That's the cycle of life, I guess."