Fish enjoyed the best win of his career on Saturday
Unseeded American Mardy Fish produced a stunning display to beat world number one Roger Federer in the semi-finals of the Pacific Life Open in Indian Wells.
World number 98 Fish served superbly and fired winners from everywhere as he raced to a 6-3 6-2 victory.
He will play third seed Novak Djokovic in Sunday's final after the Serb beat defending champion Rafael Nadal 6-3 6-2 in one hour 28 minutes.
Federer is still looking for his first title in 2008.
It is the first time since 2000 that he has not won a title in the first three months of the year.
"In the locker room we kind of think it's a joke - 'Oh my gosh, Roger hasn't won a tournament yet this year,'" Fish said.
I just couldn't get to his second serve and that was the disappointing part of today
Fish is the lowest-ranked player to beat Federer since then number 101, Richard Gasquet, beat the world number one at Monte Carlo in 2005.
The American had never beaten Federer in five previous meetings, but he completely outplayed the Swiss and won in just over an hour.
"I've been on the losing end five times to him, and he's won 53 tournaments, so I don't feel too badly for him," Fish said.
Fish won the opening three games and had a break point for 4-0 as he dominated the first set, before breaking at the start of the second.
A Federer comeback seemed certain but there was nothing there, and although he saved two match points at 5-1 down he could not deny Fish an incredible win.
"I have a great record against him and I have always controlled matches against him," said Federer.
"Today was different, a tough result. He came up playing very, very well.
"He took everything on the rise and hit winners. I just couldn't get to his second serve and that was the disappointing part of today."
Federer revealed last week that he was diagnosed with mononucleosis (glandular fever) at the start of the year but claimed to be getting back to full fitness in Indian Wells.
And despite the surprising defeat he remained happy with his efforts and in a positive frame of mind ahead of next week's Masters Series event in Miami.
"All in all, I'm happy with the way the week went for me," he said.
"Semi-finals to start off with at the first Masters Series is a good thing, and I hope I can go from here and win in Miami, and on to clay."
In the first semi, Nadal could not match last year's final win over Djokovic.
The Spaniard took a 6-2 head-to-head record into the match and grabbed an early break, but Djokovic levelled at 2-2 and broke again for 5-3 with a net cord, serving out the set with an ace.
Nadal was struggling on serve and he lost the last four games as Djokovic dominated with the Spaniard claiming fatigue was a factor in his defeat.
"I had very tough matches in the rounds before, very tight matches," Nadal said.
"You have to be 100%. He (Djokovic) played, for sure, less hours on the court than me, easier matches."