French top seed Gael Monfils and big-serving American John Isner booked a rematch of an epic 2007 semi-final showdown at the $1.4 million ATP Washington Classic with impressive triumphs on Friday.
Seventh-ranked Monfils ousted Serbian sixth seed Janko Tipsarevic 6-4, 6-4 while 35th-ranked Isner downed Serbian third seed Viktor Troicki 7-6 (7/5), 3-6, 6-1 for his 11th victory in 12 matches.
Isner owns a 3-2 career edge on Monfils, who beat Isner in their most recent meeting in 2010 at Montpelier on the way to his most recent title.
Isner won their first meeting four years ago in a Washington semi-final that went to three tie-breakers. The last played to a standing ovation, and proved the high point of the American's breakthrough run to his first ATP final.
"That was kind of a spine-chilling goosebumps moment. That's one of the matches I will always remember," Isner said.
"We always seem to have great matches. We always seem to bring out the best in each other."
Seventh-ranked Monfils must win five matches in four days to claim a fourth career ATP crown due to rain that forced him to play twice on Thursday. His only outdoor hardcourt final since 2006 came last year at Tokyo.
American Donald Young, ranked 128th, and Czech Radek Stepanek, ranked 54th, will meet in Saturday's other semi-final at the US Open tuneup event.
Young, a 22-year-old left-hander, reached the first ATP semi-final of his seven-year career by beating seventh-seeded Cypriot Marcos Baghdatis 6-3, 7-6 (7/4) while Stepanek, 32, ousted Spanish fifth seed Fernando Verdasco 6-4, 6-4.
"It means the world to me," Young said.
"This is the best I have ever done. This is where I want to be more often. Hopefully I can keep playing well at this level."
Monfils and Tipsarevic exchanged breaks in the fifth, sixth and seventh games of the match and the Frenchman then held twice to claim the first set. Monfils broke for a 2-1 lead in the second set and held out from there.
Isner, a winner in Newport and runner-up in Atlanta in July, hit a backhand volley winner on his third set point of the tie-breaker, handed Troicki the lone second-set break, then broke him three times in the third set for the win.
"I just stuck with it, tried to put more pressure on him and I guess he cracked a little bit," Isner said.
Young fought off three break points in the 12th game of the second set of his first ATP quarter-final since 2008 to reach a tie-breaker, then won the final three points of the match, the last a forehand winner after 87 minutes that left Young thumping his chest in celebration.
"I shocked myself," Young said.
"I was just doing what I was doing the whole tournament, using my forehand and moving him around a lot."
Young hit 17 winners, 11 from his forehand, and connected on 65% of his first serves to only 35% for 2010 Washington runner-up Baghdatis, who felt the effects of playing two Thursday matches due to the rain on Wednesday.
"I wasn't 100% ready, especially mentally," Baghdatis said.
Former teen prodigy Young, who would jump past his career high of 73rd in the rankings from 2008 if he reaches the final, said years of hard learning are finally paying off in new confidence.
"I actually feel like I can do it," Young said.
"I'm not going out there hoping for it. That's a big change. It definitely feels different."
Stepanek never faced a break point in the first set and denied Verdasco on 7-of-8 break chances in the second set to win after one hour and 51 minutes.
"The confidence is growing with every single match," Stepanek said.
"I have a good rhythm. Hopefully I can keep that through the weekend."