Kei Nishikori accomplished his goal and so much more at his first US Open.

The 18-year-old just wanted to win his opening match. He made it all the way to the fourth round, becoming the first Japanese man to reach the round of 16 at the tournament since 1937.

Nishikori's run ended on Monday when he lost 6-3, 6-4, 6-3 to 19-year-old Juan Martin del Potro of Argentina, the No. 17 seed.

"I think I get more confidence from this week," said Nishikori, who came in ranked No. 126.

He was only the second man from Japan to reach the fourth round at a Grand Slam tournament in the Open era: Shuzo Matsuoka was a Wimbledon quarterfinalist in 1995.

Nishikori also became the youngest man to advance this far at the US Open since Marat Safin in 1998. When he beat fourth-seeded David Ferrer on Saturday, that made him the youngest man to defeat a top-four seed at the Open since 17-year-old Bjorn Borg upset No. 3 Arthur Ashe in 1973.

A little tired

Nishikori was playing in his second Grand Slam after retiring because of an injury in the first round at Wimbledon this year.

He acknowledged he was tired on Monday, mentally and physically. Serving with a chance to tie the second set at 5-5, he was broken by del Potro to end the set. Nishikori smacked a ball into the stands in frustration.

Del Potro, who advanced to his first Grand Slam quarterfinal, kept up his sizzling play. He has won 23 straight matches and four consecutive tournaments. He next faces No. 6 seed Andy Murray.

"He's a very good player," del Potro said of Nishikori. "He has a good future. But today he doesn't play too good, but he had a very good tournament. I'm happy to be in the quarterfinals, but it's a good tournament for him, also."

(Agencies via Shanghai Daily September 3, 2008)