Swiss Federer, three times champion at Indian Wells and seeking his first ATP title of the year, will next meet unseeded American Mardy Fish, who scraped past seventh-seeded David Nalbandian of Argentina 6-3 6-7 7-6.

'I deeply regret that I have to withdraw,' Haas said in a statement. 'I was playing my best tennis of the season and was looking forward to playing Roger this afternoon.

'I am sure the tennis will be incredible this weekend and I look forward to returning again next year.' The 29-year-old, a former world number two whose career has been dogged by injuries, produced an impressive run this week, knocking out sixth-seeded American Andy Roddick and Britain's number 11 seed Andy Murray.

Top seed Federer, who has beaten Haas eight times in 10 career meetings, said: 'I am very sorry for Tommy as I was looking forward to another great match with him.

'We have played quite a few times and I know and respect Tommy a lot. I hope he gets better quickly.'

Sealed victory
Fish, who upset fourth-seeded Russian Nikolay Davydenko in the third round, squandered two match points in the 10th game of a protracted third set against Nalbandian before sealing victory in two hours, 45 minutes.

The Argentine, who had lost to Fish in their only previous career meeting, broke the American in the 11th game to lead 6-5 but failed to serve out for victory in the 12th.

Nalbandian double-faulted to be broken and Fish took late control of the tiebreak, a forehand winner putting him 6-4 up before he booked his place in the last four with an overhead smash.

'This feels great,' Fish, 26, said in a courtside interview after falling to his knees and rocking back in celebration.

'David is a tremendous opponent and he's got a heck of a record in coming back in matches, and that was in the back of my mind. It was great to have the crowd on my side.'

Saturday's other semi-final will be between holder Rafael Nadal of Spain, seeded second, and third-seeded Australian Open champion Novak Djokovic of Serbia. -- REUTERS