Second seed Kei Nishikori got off to a winning start at the rain-delayed Citi Open on Tuesday, posting a three-sets win over American Donald Young in the second round.
Nishikori, who had a first-round bye, prevailed 6-3, 4-6, 7-6 (7-5) in a match that lasted just under 2½ hours at the Rock Creek Park Tennis Center in Washington D.C.
"I was able to play my game at the start but my opponent pinned me back with his quick tennis and I made mistakes in the second set," said Nishikori. "I was lucky at the end."
Nishikori will face three-time champion Juan Martin del Potro of Argentina in the next round. No. 13 seed del Potro extended his Citi Open winning streak to 15 matches after taking down Lukas Lacko in an earlier match, beating the Slovak 7-5, 6-2.
Del Potro holds a 5-1 head-to-head record against Nishikori.
"The next match against del Potro is going to be a tough one," said Nishikori.
The 27-year-old Nishikori is aiming to win this tournament for the second time, having captured his maiden Citi Open title in 2015.
Also for Japan, Go Soeda lost in the first round after going down 7-6 (7-2), 6-3 to American Tennys Sandgren.
Nishikori has been suffering from injuries this season and made a third-round exit at Wimbledon earlier this month.
The Citi Open is considered a warm-up event for the U.S. Open kicking off later this month.
Nishikori defeated current world No. 1 Andy Murray at last year's Grand Slam event, before he lost to Stan Wawrinka of Switzerland in the semifinals.