Novak Djokovic’s four-set win over Andy Roddick was interesting enough before the postgame. Then Djokovic, the No. 3 player in the world, took swipes at Roddick after the match, earning a shower of boos from the crowd. Suddenly it became really interesting.

Unknown to everyone, Djokovic had been ticked off by comments made by Roddick two days earlier. Roddick had teased him about his frequent use of trainer during matches for a variety of injuries. It must have hit a sore spot.

“Andy said I have 16 injuries,” Djokovic said on court after a 6-3, 6-2, 3-6, 7-6 (5) win. “Obviously I don’t, right?”

He took Roddick’s comments as a suggestion that he was faking the injuries. The implication, he said, turned the U.S. Open crowd against him. That may have had some validity. The fans were fully in Roddick’s corner during the match, even making distracting noises while Djokovic served. There’s no way to know how much, if any, was from Roddick’s comments.

Djokovic sang a different tune 20 minutes later during his press conference. He apologized for exaggerating and chalked the whole thing up to a misunderstanding. Seems the source of the turnaround was a meeting with Roddick in the locker room in which they straightened things out to some degree. So the Serbian mostly ran away from his swipes while defending his use of the trainer. Interestingly, he said he wanted to use the trainer tonight but didn’t because of what people would think.

For his part, Roddick insisted he had been joking all along in his comments about Djokovic. That was mostly true—he’d included cracks about SARS and anthrax. But he also said: “If it’s there, it’s there. There’s just a lot. He’s either quick to call a trainer or he’s the most courageous guy of all time.” Some other players had also alluded to Djokovic’s injuries, so it was a real issue at least in the mind of the Serbian.

It’ll be interesting to see how the crowd reacts during his semifinal against Roger Federer.