Andy Roddick rifled his ninth ace to set up a match point and finished it off with a 6-1, 6-4 win over Juan Monaco as the American continued to lift his game at the Winston-Salem Open.
Top seed Roddick is making up for a lost summer, the majority of which he sat out with a post-Wimbledon abdominal muscle strain.
"I wanted to get off in two sets, I didn't feel the heat to be honest," said Roddick of Thursday's quarter-final match. "I've been anxious and ready to play, that set the tone for the match. He has one bad service game and the thing was over."
The former number one and 2003 US Open champion will play to reach his first final since February when he faces compatriot John Isner on Friday.
"There won't be a lot of surprises in the match," said Roddick. "He'll take a lot of risks. I'll go in with the second-best serve and that's not usually the case."
Fourth seed Isner moved into the semi-finals for the fourth time in his last six events with a 1-6, 6-3, 6-4 victory over Marcos Baghdatis of Cyprus, the player he'll meet in the US Open first round next week.
The bottom half of the draw will pit Frenchman Julien Benneteau against Dutch tenth seed Robin Haase.
Benneteau staged a fightback to upset ninth seed and 2010 winner Sergiy Stakhovsky 3-6, 7-6 (11/9), 6-2. Haas deposed third seed Alexandr Dolgopolov 6-4, 6-4.
Roddick has won three of four matches with Isner. "It's tough to execute against him, He can hit four aces in a game and suddenly you're serving again.
"I'll have to take care of serve and hope that something good happens."
The North Carolina event, which is likely to avoid the full force of Hurricane Irene, was the setting for wild card and 21st-ranked Roddick to show off the tennis which made him a regular in the top 10 for a decade, until his slide in 2010.
So solid has the revitalised Roddick been all week that he has yet to face a break point in three matches.
Isner, who lost early at the recent Montreal and Cincinnati Masters, continued to shore up his confidence with Monday's start of the US Open fast approaching.
The North Carolinian fired a dozen aces and made a huge recovery after dropping the opening set in 22 minutes to Baghdatis, a former Australian Open finalist.
Isner has taken his ace tally for the week to 39 and is pleased with how his big game is working.
"I don't give guys a lot of rhythm, that's for sure," said Isner. "I play first-strike tennis and try to keep it on my terms. I want to keep the points short and mix things up a bit."
Isner admitted he still has things to work on.
"I didn't hit the slice so well today from either side, But this is the second time I've played him this summer and I've had good success," said the American, who beat Baghdatis in Montreal a fortnight ago.