Shanghai - Andy Murray rolled into the semi-finals in his debut week at the Masters Cup, defeating Frenchman Gilles Simon 6-4, 6-2 in a Red group showdown on Wednesday.

The Scot polished his record to a perfect 2-0 as he beat the last player to enter the eight-man field. Simon gained a place at the last minute when world number one Rafael Nadal pulled out with a knee injury which will require a month or more to fully heal.

'Simon obviously is playing the best tennis of his life and he's in the top 10," said Murray.

"To beat a couple of top 10 players back to back is great. The Masters Cup is obviously a huge, huge competition for all the top players. I've got a chance of winning it now."

Roger Federer was fighting to stay in the chase later as the Swiss holder faced Radek Stepanek after losing an opening match to a Simon comeback effort on Monday.

Czech alternate Stepanek was inserted into the field when Andy Roddick withdrew just hours before the match with a turned ankle.

"In practise I just went over on it, we tried as much as we could to get it better," said Roddick. "I can't really stop and start very quickly. It's anything when I go kind of over on the outside it hurts.

"I do a lot of that a lot on my serve also, so it's definitely a tough prospect trying to beat Roger with no serve and not being able to move much.

"It's unfortunate for this event, but I don't think we're looking at anything more than a week or so," Roddick said.

Murray took a 4-0 lead in the first set against Simon, and had two points for 5-0 before the Frenchman went into recovery mode.

Murray lifted the first set as Simon pounded a backhand into the net, then went down a break in the third game of the second set.

Murray dominated from that point on to ease to victory in just over 90 minutes with his French opponent hampered by 37 unforced errors.

"Today I felt perfect," said the Scot. "I could have gone three, four hours if I had to. That gave me a lot of confidence.

"I was not doing as much running as him."

Murray improved to 3-1 over Simon, whom he also defeated in the Madrid Masters final last month. (dpa)