Murray remains modest

John McEnroe and Bjorn Borg may have backed Andy Murray to win a grand slam, but the British number one is refusing to get carried away.

World number four Murray earned his trip to the season-ending Masters Cup in Shanghai after claiming five titles in 2008 and also reaching the US Open final.

McEnroe and Borg have heaped praise on the 21-year-old Scot, who beat Andy Roddick 6-4 1-6 6-1 on Monday, but Murray said: "It's nice to hear those things from two of the greatest players ever but you still have to work very hard."

He added: "If I want to win a Grand Slam I'm going to have to work even harder than I did this year, improve my game, then there's a chance I'll do it.

"But I'm not going to say for sure that I'll win a Grand Slam next year."

At Qi Zhong Tennis Stadium on Monday, Murray looked on course for a regulation win over Roddick after serving his way through the first set.

But after Roddick fought off a break point at the start of the second set, a fatigued Murray barely figured as the world number six picked up his own service game to level the contest.

However, Murray rediscovered his form to breeze through the final set to record a fourth career victory over Roddick.

"There's no question that he's improved this year. There's no question that he's very confident right now, that's probably the main difference," Roddick said.

"He could always play tennis, he's always had his choice of many shots at any given time. I think he's just maybe a little bit more confident playing on some bigger stages. I think he's really established that this year."