Murray seeks to maintain his mastery of Federer

Roger Federer shrugged off his defeat to Andy Murray in an exhibition match last week, insisting he had taken the chance to experiment with his game, but the stakes will be higher when they meet again today in Doha.

The Qatar Open is the only tournament the two men have entered before the Australian Open, which begins in 10 days' time, and Federer will be keen to prove that the 21-year-old Scot does not have his number. The British No 1 has won four of their last five competitive matches and his victory in their last meeting knocked Federer out of the Tennis Masters Cup.

Murray, who was the game's form player in the latter half of last season, beat James Blake, Federer and Rafael Nadal on his way to victory in last week's exhibition event in Abu Dhabi. Yesterday he secured his third win of the week in Doha, beating Sergiy Stakhovsky 6-4, 6-2. The first set was tight, with early breaks of serve exchanged, but the turning point came when Stakhovsky played a poor service game to trail 5-4.

The Ukrainian, who lost to Murray in the final of the 2004 US Open junior event, initially had the Scot on the back foot with his attacking play, but the world No 4 took command after serving out for the first set. "I'm happy with the way I'm playing now," Murray said afterwards. "I don't see any reason to doubt my chances in the semi-final either."

Federer had more trouble disposing of Philipp Kohlschreiber, beating the German 6-4, 7-6, but welcomed the challenge. "It's nice to be tested at this stage in the tournament," he said. "I was 4-1 up in the second set and I was cruising, but then suddenly he came back."

There was a major surprise in the other half of the draw, with Gaël Monfils beating Nadal 6-4, 6-4. The world No 1 never found his rhythm as Monfils powered to his first win over the Spaniard in four attempts. Both sets finished in the same fashion, with Nadal dropping his serve in the final game. Monfils plays Andy Roddick in today's other semi-final.

"I didn't play my best," Nadal said afterwards. "He was very aggressive and he served very well. It's not easy at the beginning of the year."