Andy Murray insists he is in good shape ahead of his third-round clash with Dmitry Tursunov at the Cincinnati Masters later today.

The British No1 recovered from a bad start to defeat American Sam Querrey 7-6, 6-1 yesterday, continuing his good form in reaching the Toronto semi-finals last week.

Murray needed treatment on his knee injury during his defeat by Rafael Nadal in Canada and had a scan on Monday.

The American hardcourt season, culminating in the US Open at the end of next month, is Murray's favourite stretch of the year, while the Olympics in Beijing provide an extra prize this season. And the Scot is confident both his game and his body are up to the task.

"The knee is fine," he said. "I've known about it for five years, it's something that comes and goes and is just a bit of inflammation around the kneecap.

"I've played a lot of matches and I feel good. I'm chasing a lot of balls down, I feel fast on the court and I'm hitting the ball harder."

Murray made the worst possible start against Querrey, losing his opening service game and falling 3-0 behind. But Querrey was mixing thumping winners with a rash of unforced errors as Murray first broke back then comfortably won a first-set tie-break.

The second set saw the eighth seed step up a gear and Querrey eventually ran out of ideas as Murray neutralised his power game.

The 21-year-old put his sluggish start down to the difference in conditions between Cincinnati and Toronto. "I didn't feel that comfortable," he said. "It's so fast here compared with last week.

"The balls are flying around and you feel like you can't really swing at the ball as hard as you could last week.

"I've played a lot of matches at night - my last few matches the balls have been dead and here they're flying though the air so quick and I was struggling to control the ball, so I was getting a bit frustrated.

"But once I calmed down and played a few more games then I started to serve better."