'Terrible' Djokovic battles to keep his great season alive

So much for the world's top three players. Twenty-four hours after Andy Murray pulled out of the Barclays ATP World Tour Finals with a groin strain and an out-of-sorts Rafael Nadal suffered his heaviest defeat for nearly four years, Novak Djokovic was beaten 6-3, 6-1 by David Ferrer here last night. The world No 1 said he played a "terrible, terrible match".

As the demands of a gruelling season take their toll, Roger Federer could be the only member of the game's big four to reach the semi-finals, having already booked his spot with his crushing victory over Nadal, who has to beat an in-form Jo-Wilfried Tsonga tonight to earn his place.

Meanwhile Djokovic may need to beat his fellow Serb, Janko Tipsarevic, in his final round-robin match tomorrow. "If I don't play 50 per cent better than I did tonight, I don't think I'll have any chance," he said.

Djokovic looked a pale shadow of the man who has enjoyed one of the best seasons in history, winning 10 titles, including three Grand Slam tournaments. As Ferrer secured his own semi-final place, Djokovic made 33 unforced errors and hit only 10 winners in suffering just his fifth defeat of the year.

"I'm embarrassed to look at the stats," Djokovic said. "I did not give him any resistance, nothing." He added: "I'm not playing well. That's a fact. Maybe it's because of the length of the season."

Both Djokovic and Nadal have looked worn out this week, while a disconsolate Murray pulled out the day after losing to Ferrer. The world No 3's replacement was Tipsarevic, who said after losing 2-6, 6-3, 7-6 to Tomas Berdych yesterday that he had been surprised by Murray's withdrawal.

Tipsarevic, who cannot now make the semi-finals, practised with Murray for an hour and a quarter on Sunday. The Serb said they played a set before Murray curtailed the scheduled 90-minute session. When the Scot explained his withdrawal on Tuesday he said only that he had "played some points" with Tipsarevic but then "stopped the practice early".

Recalling the practice session, Tipsarevic said it had "never crossed my mind" that Murray could be injured. As for Murray's match against Ferrer, Tipsarevic added: "I felt that he was running OK but wasn't feeling good on the court. I honestly never thought that he had a physical issue."

This tournament is in its third year in London, but the chances of it staying here beyond the current five-year deal could depend on Chancellor George Osborne's Budget statement in March. The Lawn Tennis Association are keen to keep the event but know that some leading players are unhappy at having to pay tax on their endorsement deals for every day they spend in Britain.

Roger Draper, chief executive of the LTA, said here yesterday that he had been lobbying the Government, arguing for the event to be among those exempted from the tax ruling. A number of other sports have been making similar representations.

Draper argued his case with David Cameron when the Prime Minister visited the National Tennis Centre in Roehampton last month and this week received a letter from the Chancellor. "We're hopeful we will see some exemptions in this area in the March Budget statement," Draper said. "I think there is sympathy there."

The finals have been played in numerous cities, including Sydney, Shanghai and Houston, and London is sure to have competition when talks on a new deal begin next year. One factor in London's favour is the revised calendar. In future the finals will be staged back-to-back with the Paris Masters, the latter finishing on Sunday 4 November next year with London starting the next day – and the players would not want to be travelling too far between the two events.