Daniil Medvedev sarcastically praised a hostile crowd for their support, despite being booed as he beat Feliciano Lopez to reach the fourth round at the US Open.
The in-form Russian fifth seed maintained his hopes of winning a maiden Grand Slam title with a 7-6 (7-1) 4-6 7-6 (9-7) 6-4 win against the Spaniard during the night session in New York.
Medvedev received an unsportsmanlike conduct code violation for snatching a towel from a ballperson's hands in the first set, before he later made an offensive gesture in the direction of the crowd.
When Medvedev's gesture - which was initially unseen by chair umpire Damien Dumusois - was shown on the replay screen, the crowd booed him loudly
"The energy you are giving me right now I think it will be enough for my next [four] matches," Medvedev said in his on-court interview through a chorus of boos.
"The more you do this the more I will win for you. Thank you, I want all of you to know when you are asleep tonight I won because of you."
The 23-year-old, who won the Cincinnati Masters, will face world No 118 Dominik Koepfer of Germany in the last 16.
"I cannot give you a code because of what I saw on the screen. I have to see it myself," Dumusois told Medvedev after his gesture was shown courtside.
Meanwhile, Novak Djokovic shrugged off concerns about his fitness to defeat Denis Kudla in straight sets at Flushing Meadows.
The defending champion needed extensive treatment on a shoulder problem during his second-round match.
But Djokovic showed no obvious discomfort in a 6-3 6-4 6-2 win over American Kudla.
"What pleased me most is that I managed to play almost pain free, that's a big improvement on my last match," he said.
"I'm not going to go into medical details, but it was bothering me over the last couple of weeks and especially in the last match."
Djokovic, who is targeting a fourth title in New York, will next face former champion Stan Wawrinka in his last-16 match on Sunday.
He added: "We've had some great battles over the years, everywhere.
"I lost to him last time we played here, in the final in 2016. He has a lot of power, a lot of quality. Let the better player win."
Wawrinka got through in straight sets against Italian lucky loser Paolo Lorenzi, winning 6-4 7-6 (11-9) 7-6 (7-4).
David Goffin, the 15th seed, beat Spain's Pablo Carreno Busta 7-6 (7-5) 7-6 (11-9) 7-5 to book a meeting with 20-time Grand Slam champion Roger Federer, who knocked out British No 2 Dan Evans.