Djokovic surges on but Murray faces running out of time

There is no stopping Novak Djokovic. The 24-year-old Serb, playing in his first tournament since becoming world No 1, maintained his extraordinary run of success when he won the Montreal Masters last night. In beating the American Mardy Fish 6-2, 3-6, 6-4 in the final, Djokovic became the first man ever to win five of the nine Masters Series titles in the same year. Three of the tournaments still have to be played.

Djokovic has played 54 matches this year and lost just once, to Roger Federer in the semi-finals of the French Open. He has won ever other tournament in which he has competed, including the Australian Open, Wimbledon and the Masters Series events in Indian Wells, Miami, Madrid, Rome and now Montreal. The year's final Grand Slam tournament, the US Open, begins in a fortnight's time, while the next Masters event is taking place in Cincinnati this week.

While there is no sign of a drop in Djokovic's form, the next three players in the world rankings will all be hoping for a good run in Cincinnati after making early exits in Montreal. Federer won only one match before losing to Jo-Wilfried Tsonga, while Rafael Nadal and Andy Murray lost first time out, to Croatia's Ivan Dodig and South Africa's Kevin Anderson respectively.

For the last two years Murray has gone into his final tournament before the US Open at the top of his game, but as the world No 4 prepares for Cincinnati he knows that time is running out if he is to find his form before the concluding Grand Slam event of the season. After deciding to play only two tournaments in the build-up to New York, the Scot has given himself little room to manoeuvre.

Part of Murray's thinking was that he may have peaked too early in his last two summer hard-court seasons in north America. On both occasions he won the first Masters Series title of the campaign in Canada only to falter subsequently at Flushing Meadows. The US Open, where Murray won the junior title and reached his first senior Grand Slam final three years ago, has traditionally been his favourite event, but on his last two visits he has gone out in the fourth round to Marin Cilic and in the third to Stanislas Wawrinka.

A successful week in Cincinnati would put Murray back on track, though the draw has not made life easy for him. After a first-round bye his second-round opponent could be David Nalbandian, while Tsonga could await in the third, although the Frenchman retired hurt with an arm injury against Djokovic in the semi-finals in Montreal. Murray is seeded to meet David Ferrer in the quarter-finals and Nadal in the semi-finals.

Serena Williams extended her remarkable winning to 11 matches when she beat Australia's Sam Stosur 6-4, 6-2 in the final in Toronto last night. Williams, who returned to competition in June after 11 months out of the game, has won both her tournaments since Wimbledon and has quickly established herself as the favourite to win the US Open for a fourth time.