Roger Federer has lost the semifinal of the Qatar Open, beaten by defending champion Andy Murray 6-7 (6-8), 6-2, 6-2.
In the first set, Murray led the tiebreak 6-5 but Federer managed to hold out by winning three points in a row. After that Murray dominated to the end of the match.
"It is disappointing to lose after the first set when things were going my way," Federer said. "I just couldn't give the knockout punch. But it is not a big thing."
"Andy is a tough player against me," he added. "I hope when big matches come, I beat him."
Federer has 13 grand slam titles, one short of Pete Sampras's record, heading into the Australian Open later this month.
Since losing to Federer in the US Open final, the fourth-ranked Murray beat the Swiss star at the Madrid Masters in October, the Masters Cup in Shanghai in November and an exhibition tournament in Abu Dhabi last week.
Federer committed four double faults in Doha on Friday and 37 unforced errors. While Federer failed to break serve, Murray converted four of six break points.
Murray took an injury time-out in the third set for treatment to his lower back, but showed no signs of trouble as he closed out the match.
"It is good to have beaten him [Federer]," Murray said. "He is an awesome player, arguably the greatest player of all time. So, I am happy about my performance today."
Earlier on Friday, Andy Roddick reached the final by defeating Gael Monfils 7-6 (1), 3-6, 6-3. Murray will now face Roddick in Saturday's final.
The defeat at Doha is an inauspicious start to the year for Federer, with the Australian Open in ten days.
Things began to go wrong for him last January when he lost to Novak Djokovic in the semifinal of the Australian Open, an event he had won three times before.
Andy Murray then upset him in the first round in Dubai, handing Federer his second loss in a row for the first time since 2003 and his first opening-round defeat since 2004.
Explaining his unusual vulnerability, Federer revealed in March he had suffered a bout of mononucleosis, or glandular fever, at the end of 2007.
The illness appears to have triggered his loss of form, which culminated on August 18 in Spanish rival Rafael Nadal replacing him as world number one after a record 237 weeks at the top.
swissinfo with agencies
Selected 2009 schedule
Federer started the year on hard courts at an invitation tournament in Abu Dhabi then was scheduled to play events at Doha, Qatar, and Kooyong, Australia, before the Australian Open starts on January 19 in Melbourne.
Federer will play only two clay-court tournaments in 2009 before the French Open, the only grand slam tournament he has never won. He will head to Paris on May 24 after playing Masters series events on his least-favourite surface in Rome and Madrid. He played four clay-court events in 2008 ahead of the French Open – Estoril, Monte Carlo, Rome and Hamburg.
His grass-court schedule is unchanged with a single warm-up for Wimbledon, which starts on June 22, at Halle in Germany.
Federer will defend his US Open title from August 31 after playing Masters events on hard courts at Montreal and Cincinnati.