Los Angeles - Top seed Mardy Fish survived a brave fightback by fellow American Ryan Harrison to reach the Los Angeles ATP final with a 6-0 4-6 7-6 win on Saturday.
Fish won the third set tiebreaker 7-3 in bright afternoon sunshine, closing out the match with his seventh ace after a see-saw contest lasting two hours 11 minutes at the LA Tennis Center.
In the other semi-final match Latvia's Ernests Gulbis knocked off American Alex Bogolomov in straight sets 6-2 7-6 to advance to his second career final.
Gulbis won the second set tiebreaker 7-4.
"Being in the final is very big for me, I'm on a comeback and this is a boost for my confidence," said Gulbis. "I have chances in the final."
Gulbis won the International Tennis Championship in Delray Beach in 2010.
Ranked 21st in the world as recently as February, Gulbis entered the tournament on a five-match losing streak and is currently ranked 84th.
LA resident Fish, who won his sixth ATP World Tour title at last week's Atlanta Tennis Championship, raised both arms in triumph after scraping past the 19-year-old Harrison.
"He kept his level and credit to him," Fish said courtside, having stormed into a commanding 5-0 lead in the tiebreak before clinching the match.
"He came out in the second set and fought hard and didn't give up, didn't let the moment get to him. He could have easily won that match.
"Tiebreakers are kind of a coin flip out here. I was lucky enough to get up there and put some pressure on him at the end."
Fish, who beat Harrison in straight sets in the semi-finals in Atlanta last week, was delighted with his own form in a one-sided opening set at the LA Tennis Center.
"That was probably the best set of tennis I have played all year," the 29-year-old said. "I lost five, six points and it was as clean of a set as I could possibly play."
However, Fish also paid tribute to Harrison, who is widely regarded as one of the most exciting young prospects in American men's tennis.
"This is only the second semi-final of his whole career," Fish said. He's way ahead of where I was at 19 and I have a lot of respect for his game."