Overview

• Daniel Altmaier beat Stefanos Tsitsipas 7-6(5), 1-6, 4-6, 6-3, 7-5 in a four-hour 26-minute US Open second-round match.
• Tsitsipas failed to convert a match point, then told Altmaier at the net, "Next time, don't wonder why I hit you... if you serve underarm."
• Altmaier used the legal but uncommon underarm serve several times, and the crowd booed during the frosty exchange as he backed away.
• Tsitsipas has not reached a third round at a major this season and has slipped to No. 28, with one win in his last seven matches after parting with Goran Ivanisevic and reinstating his father as coach.
• World No. 56 Altmaier advanced to the US Open third round for the first time and will face eighth seed Alex de Minaur next.