Paul Goldstein has won matches on the courts of Wimbledon, the most storied grounds in tennis. He won the gold medal for the United States at the Pan Am Games this month. But until last night, he had never been able to win a match in his own backyard.

The Rockville native's luck changed with a 7-5, 6-4 victory over fellow American Cecil Mamiit in the first round of the Legg Mason Tennis Classic, his first win in four tries on the grounds of the William H.G. FitzGerald Tennis Center.

The match led a mixed day for the Americans, who saw Justin Gimelstob upset No. 15 seed Richard Fromberg, 6-4, 2-6, 7-6 (7-4), but No. 11 seed Jan Michael Gambill ousted by Denmark's Kenneth Carlsen, 7-6 (7-3), 4-6, 6-4. No. 13 seed Michael Chang, who has won this tournament twice, capped things off with a 6-0, 6-1 drubbing of qualifier Nenad Zimonjic.

Chang's win took just 37 minutes, but by the time he stepped off the court at 12:09 a.m., much of the crowd had already left, their energy spent on Goldstein. The 24-year-old was appreciative as he walked off the court, waving to his family and many of his friends.

"It really is a relief," Goldstein said of the win. "I can't emphasize enough how badly I wanted to win at this tournament for all the people who have supported me. I was a little tight today because I wanted to do well in front of everyone, but it was great."

While Goldstein is enjoying his highest ranking ever, No. 97 compared with No. 264 at this time last year, he got no break in playing Mamiit, who may know Goldstein's game better than anyone else in the draw. The two are doubles partners. They share the same coach, Scott McCain. They have spent time at each other's houses -- Mamiit had dinner at the Goldsteins on Friday -- and countless hours across from each other in practice sessions.

They have also seen plenty of each other in match situations, most recently at the Pan Am Games in Winnipeg, Manitoba, where they played for the gold medal. Goldstein defeated Mamiit, 4-6, 6-0, 6-3, but he took more than the title away from the event. He said he saw a feeling of solidarity grow among the U.S. players, a trend that has been filtering through the men's game since the spring.

"It was great to feel the camaraderie I felt during college, and it's something I'd really like to see continue over into the Tour," said Goldstein, who graduated from Sidwell Friends School in the District, and then Stanford University last year. "You saw it today, at the end of Justin Gimelstob's match, a bunch of us were out there watching, supporting him. Todd Martin was sitting with me for all of Justin's first set -- we're starting to do that more, and I think it's a real positive thing in the game. For me, it's been a big help."

Goldstein needed all the support he could get in the first set as the players traded points like baseball cards. Goldstein finally took control of the set by winning three straight games, and he appeared in charge of the second set as well when he jumped out to a 4-0 lead.

But Mamiit, who had become so overwrought earlier in the set that he fell to his knees after one point and kicked over a sideline bench after another, finally began to find his rhythm. He battled back to 4-4, and when he started the set's ninth game by hitting the ball between his legs for a winning lob, it appeared he was on an unstoppable roll.

That was when Goldstein returned to fighting form as well, however, and the two scrapped through several deuces before Goldstein finally won the game to go up, 5-4. He then won the match on his fourth match point, returning Mamiit's serve with a searing backhand that landed at Mamiit's feet.

"Paul felt a lot of pressure to win here, but I just told him to relax and make it happen," said McCain, who was trying hard to cheer equally in the stands. "These two are going to be playing each other for a long time."

Gambill lost his match despite going up a break on Carlsen in the third set.

The upset was the latest installment in a disappointing summer for the 22-year-old American, who has not won back-to-back matches since March.

"I've had no consistency in my game," Gambill said. "One game I'll serve well and the next I don't. The last few weeks have been very difficult. I've been losing too many close matches."

Carlsen looked comfortable early in the third set, when he cruised out to a 3-0 lead, but Gambill won the next four games to go up a break. That was all he could muster, however, as Carlsen won the next three games and the match.

"I got a little luck in the end," said Carlsen, referring to two balls that grazed the net cord before falling in his favor. "It was pretty disappointing to lose four straight games there, but I was able to pick it up in the end."

Chang had the easiest day of any of the Americans, controlling Zimonjic in every facet of the match. The win was a good start for Chang, who has been trying to rebuild his career after a difficult year and a half.

"I don't think there are any easy matches, but today was comfortable," Chang said. "It's nice to be back in D.C. It's been a good place for me and I'd like to keep that going."