New York: Two Asian teenagers have advanced to the second round of the US Open, set to make warnings of a rising young generation of stars come true on tennis` biggest stage.
Japanese qualifier Yoshihiro Nishioka outlasted France`s Paul-Henri Mathieu 6-4, 2-6, 6-7 (7/9), 6-1, 6-2 after three hours and 22 minutes in sweltering heat while South Korea`s Chung Hyeon ripped Australian James Duckworth 6-3, 6-1, 6-2 in 96 minutes.
Chung, ranked 69th, and 128th-ranked left-hander Nishioka -- both 19 -- are the lone remaining teens among 10 that reached the men`s main draw, the most at the US Open since 12 teens made the lineup in 1990.
One of them, Pete Sampras, won his first of 14 Slams at age 19.
"We didn`t have one generation like this for a while. They are here now. That`s good for tennis," said Spanish star Rafael Nadal, who won the first of his 14 career Slam titles at age 19 at the 2005 French Open.
"The best player will be the one to improve more. That`s the thing that will make the difference on this new generation."
Nishioka, who turns 20 on September 27, will face Brazilian 30th seed Thomaz Bellucci in the second round and could see British third seed Andy Murray in the third round.
It was the first main-draw Slam victory for Nishioka, who made his Slam debut at last year`s US Open.
"I`m very happy to win the first round because it`s the first time I`ve been won in a Grand Slam," Nishioka said. "After the last point, I was pretty tired."
But Nishioka had been working out in Florida heat last week, saying he was accustomed to the conditions.
"I was training at IMG (Academy) for a few days before the US Open qualifying," he said.
Swiss fifth seed Stan Wawrinka, the reigning French Open champion, will be the next foe for Chung, who fired 10 aces and landed nearly 70 percent of his first serves while dropping only six points on second serves in advancing without facing a break point.
"He`s really good mentally," Duckworth said of Chung. "He doesn`t get down when something goes wrong. Definitely he has won a lot of matches to get into the top 100. That has to build up a lot of confidence."
Chung made his Grand Slam debut this year at Wimbledon, falling to Frenchman Pierre-Hugues Herbert in five sets, surrendering only after pushing the last to 10-8.
Three teens were toppled on day one, most notably Croatian Borna Coric despite pushing Nadal to a fourth set.
Five others fell Tuesday, but some made impressive fights.
Aussie Thanasi Kokkinakis was leading in the fourth set and poised for an upset of French 12th seed Richard Gasquet but began cramping.
He battled through but retired in the fifth set after two hours and 51 minutes.
Russian qualifier Andrey Rublev, 17, tested South African 15th seed Kevin Anderson before losing 7-6 (7/1), 6-7 (5/7), 7-5, 6-3.
And 18-year-old German qualifier Alexander Zverev took 29th-seeded countryman Philipp Kohlschreiber this distance before falling 6-7 (0/7), 6-2, 6-0, 2-6, 6-4.