Defending champion Novak Djokovic groaned and grimaced but lives to fight another day after battling past Jerzy Janowicz in the US Open first round.
Djokovic admitted last week an injury to his left wrist had not completely healed but it was a problem with his right elbow that seemed to cause the top seed most discomfort in Arthur Ashe Stadium.
The Serbian called the trainer just five games in and then moped his way through the rest of the contest en route to a 6-3 5-7 6-2 6-1 victory over the Pole.
Djokovic will now face Jiri Vesely in round two after the Czech won a marathon five-set match against India's Saketh Myneni.
Asked about his fitness problems on court after the match, Djokovic said: "It's never easy to play at this level throughout the year.
"There are periods of the year when you're not feeling 100 per cent. I don't think it's necessary to talk about it now. I'm through. I'm taking it day by day and let's keep on moving."
Djokovic may yet recuperate - he has proved his powers of recovery before - but his body will have to pass far stiffer tests if he is to lift a 13th grand slam title in two weeks' time.
Opening the first night session of the tournament, Djokovic and Janowicz had to wait for the conclusion of a lavish ceremony to unveil the stadium's new US dollars 150million roof, before it was their turn to play.
Billie Jean King introduced the celebration and Phil Collins delivered a rendition of 'In The Air Tonight' as the roof's two panels gradually slid open.
"It was hard to put up a show after Phil Collins, he's a legend," Djokovic said afterwards, before jigging on the court and singing: "I can't dance, I can't talk. The only thing about me is the way I walk."
After taking treatment on his right elbow at 3-2 in the opening set, Djokovic immediately broke his opponent and served out the opening frame.
The 29-year-old did not look comfortable, however, and after an exchange of breaks midway through the second, Janowicz broke again at 6-5 to level at one-set all.
Leaping about the court in celebration, Janowicz looked up for the fight but he was too careless to capitalise and Djokovic stormed clear in the third.
Any momentum Janowicz had, quickly fizzled, and Djokovic broke three times in the fourth to wrap up victory in two hours and 37 minutes.
"It was overall a good performance especially in the third and fourth," Djokovic said.
"Jerzy is an unpredictable player, he has a big serve, he can serve over 140 miles per hour and when the ball comes at that speed, the only thing is react and pray you can get the ball back.
"It wasn't to be in the second set but overall it was a good performance."
Source: PA
