Rafael Nadal has conquered the French Open 10 times and battled career-threatening knee and wrist injuries, but his greatest challenge awaits him -- telling rowdy New Yorkers to be quiet.
The world number one and two-time US Open champion took his first-round record at the season's concluding Grand Slam to 13-0 on Tuesday with a 7-6 (8/6), 6-2, 6-2 win over Serbia's Dusan Lajovic.
But with torrential rain lashing the Flushing Meadows site, the roof on the showpiece Arthur Ashe stadium was shut tight, creating a giant echo-chamber for the boisterous crowd of 24,000 beneath.
"Being honest, it (the noise) is a little bit too much," said the 31-year-old Spaniard, whose Grand Slam collection of 15 titles includes the 2010 and 2013 US Open crowns.
"The energy and support of the crowd is massive. I enjoy it and I have unforgettable memories from this tournament and this court, because the energy is different from in other places.
"But at the same time, under the roof, it's too much noise. I was not able to hear the ball when hitting.
"I understand it's a show, but under the roof we need to be a little bit more strict about the noise. All the noise stays inside, and this is difficult."
Nadal's complaints echoed similar concerns made by Andy Murray last year when the huge $150 million roof over the world's biggest tennis stadium was rolled into action for the first time.
Murray, the 2012 champion, claimed that when the rain was bouncing off the outside of the roof, it was impossible to hear line calls inside.
Even the umpire in that match appealed to spectators to cut the volume, a desperate and often futile appeal during the tournament's famed night sessions when the alcohol-fueled atmosphere is not for the meek.
Nadal said the noise on Tuesday meant that he was unable to hear the ball and that his opponent couldn't hear him when he asked for a service game to be delayed.
Meanwhile, Nadal said he was equally flummoxed by Murray's decision to withdraw from the US Open last Saturday -- after the draw had been made.
Murray was suffering from a hip injury and his decision to pull out of the event, where he would have been second seed, came too late to affect Nadal's half of the draw which he shares with old rival Roger Federer.
"Was a little bit strange that he retired just the morning after the draw was made," said Nadal.
"You don't retire Saturday morning. You retire Monday morning or Sunday afternoon. If not, you can do it before the draw. That's why I say it's strange."
"Was something that is a little difficult to understand, but the worst thing is he is not healthy and I wish him a very fast recovery."