Radek Stepanek defeated top seed Andy Roddick 3-6 7-6 (7/5) 6-4 to reach the final of the SAP Open.
The fourth seed from the Czech Republic will now face Mardy Fish, who toppled an injured James Blake 6-3 6-2 in the other semi-final.
After losing the first set to Roddick, Stepanek battled and scrapped his way into a tiebreaker before levelling the match.
He then claimed a crucial break in the final set and finally held serve to seal victory.
Stepanek faced a break point in the final game but served his 12th ace before double-faulting to give Roddick further hope.
Roddick earned another advantage point but Stepanek once again brought the game back to deuce and won the next two points to triumph after two hours and 13 minutes.
Stepanek showed all his resilience as he withstood 19 aces from Roddick and fought off ten of 11 break points.
In the opening semi-final, Fish used a strong serve to claim victory over the third-seeded Blake.
Fish sent down 16 aces and won 27 of 29 points on his first serve to defeat his friend and doubles partner in an hour.
Fish has not been broken in his last three matches and was so dominant that Blake did not even have a break opportunity.
Blake injured his ankle on Friday in a quarter-final win over Sam Querrey, which affected him against Fish.
‘I had no idea his ankle was that bad,’ Fish said. ‘It's just a testament to James. He's never defaulted in a match in his career.’
Blake was 1-2 down in the first set when he asked for a trainer and had his ankle retaped before he did the same at the end of the first set.
‘It affected me more than I thought it would have when I did it,’ Blake said.
‘I just iced it a few times yesterday and taped it up. I thought I'd be ready to go.’
The trainer told Blake that he would not do any more damage, so the third seed played on.
‘I thought if I wasn't going to hurt it any more, I could suck up the pain for 20 minutes, 30 minutes and make it a little better for the fans, hopefully, and better for Mardy to feel like he earned a victory, which he did,’ Blake added.
