Novak Djokovic defeated Hungarian Marton Fuscovic in straight sets at the French Open, 7-6(2), 6-0, 6-3 and is through to the third round. There awaits the Spaniard Alejandro Davidovich Fokina.
After the match, a detail on the world number three's chest has attracted attention.
During the meeting, a metal-like button was seen taped to Djokovic's chest. During the game, via a ball girl, he received a new button from his staff, he removed the tape and attached the new button.
Cryptic post-match response: "If it weren't for it..."
He ducked questions about the button after the game.
"When I was a kid, I liked Iron Man a lot, so I try to be like Iron Man," he said at the press conference.
The Serb was not keen to tell us more.
"My team delivers incredibly effective nanotechnology to help me do my best on track. So that's the biggest secret of my career. If it weren't for it, I probably wouldn't be sitting here," he says.
See the pictures the hidden object in the player above.