Federer quest undermined by nemesis Nadal

It was only the second time that Federer has lost this year and both defeats have been at the hands of the 19-year-old Spaniard, who has now won all but one of his five matches against the world No 1. While Federer had come here saying he would be happy simply to better his exit at the quarter-final stage 12 months ago, it could prove an important psychological setback during a clay-court season in which the Swiss hopes to become the first man since Rod Laver to hold all four Grand Slam titles at once.

The French Open is the only jewel missing from Federer's crown and Nadal, who won at Roland Garros last year after a season in which he totally dominated on clay, is the man most likely to thwart his ambitions. The world No 2 is now unbeaten in 42 matches on clay; in the Open era only Guillermo Vilas (53 matches) and Bjorn Borg (46) had longer winning runs.

Unlike last month in Dubai, where he lost to Nadal after being totally in command in the first set, Federer rarely looked at ease here. He knows he does not play enough against left-handers ­ in 70 matches since he lost to Nadal in Paris last year only three have been against "lefties" ­ and the Spaniard's forehand, in particular, is a shot to which he all too frequently succumbs.

Nadal concentrated his attack on his rival's weaker backhand side, though the flow of Federer errors came from both flanks. Mishits were frequent and when he did find his racket's sweet spot the ball regularly flew wide, long or into the net. Federer feels he has to play aggressively against such a dogged retriever, but perhaps he still needs to find the right balance between attack and defence.

Federer said he was not concerned by the number of errors and was pleased with "a fantastic week". He felt he had run Nadal closer than when losing at Roland Garros last year. Nadal said it had been "special" to retain his Monte Carlo title by beating the world's best player.

With Federer miscuing badly at the start, Nadal had raced into a 4-0 lead. The Spaniard failed to convert two set points at 5-1, but served out to draw first blood.

Federer, who had made 24 unforced errors in the first set, fought back from a break down in the second, saved a set point and played an immaculate tie-break, which he won 7-2. When he broke serve in the first game of the third it was the first time he had led in nearly two hours of tennis, but Nadal hit back immediately and made another decisive break in the eighth game.

Nadal broke twice to lead 3-0 at the start of the fourth set, whereupon Federer, infuriated by a line call, smashed a ball out of court, and received an official warning. The world No 1 fought back to 4-4 and took a 3-0 lead in the tie-break, only to lose seven of the last nine points, Nadal sealing victory with a thumping forehand. It was only the second tie-break out of 15 that Federer has lost this year.

Until he faced David Nalbandian in the final of the Masters Cup in Shanghai five months ago Federer had won 24 finals in succession. Now he has lost three of his last seven. Although he has still lost only six matches since the start of last year, the fact that three of them have been against Nadal might just be starting to trouble tennis' coolest head.

* Britain's women were beaten 2-0 by Slovakia in their Fed Cup promotion play-off in Plovdiv, Bulgaria, and will therefore remain in the Europe/Africa Zone.