CHELSEA believe that the Premiership title race took not only a dramatic but also a decisive turn in their favour last night when, after they had beaten Tottenham Hotspur 1-0 at home in the day’s early kick-off, their rivals Manchester United lost 2-1 to Portsmouth at Fratton Park to cut the gap at the top of the table to three points, both teams having played the same number of fixtures.

Jose Mourinho, the Chelsea manager, was quick to remind everybody that United have still to play at Stamford Bridge, on May 9. “That’s the game when they can let it slip,” he said. “That is the only thing we can control.”

Mourinho’s team beat Spurs 1-0 at lunchtime, with a 30-yard strike from Ricardo Carvalho, the Portuguese defender and man of the match, whose three goals in the league this season also include the equaliser when Chelsea drew 1-1 at Old Trafford in November.

Their lead at the top of the table having been reduced from six points for the first time since December, United’s nerves showed in the evening kick-off, when their goal-keeper Edwin van der Sar was at fault as Matthew Taylor gave Pompey the lead and defender Rio Ferdinand put through his own goal in the 89th minute.

There was still time for John O’Shea to pull one back, courtesy of a handling error by David James, who was otherwise outstanding in the Portsmouth goal, but it was too late to affect the outcome.

United felt that they should have had a penalty in the 69th minute, when Wayne Rooney took a tumble in the area under challenge by Linvoy Primus, but television replays suggested that the referee Mark Clatten-burg had made the correct decision. Sir Alex Ferguson, the United manager, also complained, with greater justification, that Rooney had been wrongly flagged offside when in a scoring position.

Ferguson admitted the day’s two results had been “a big psychological boost for Chelsea”, but said: “With six games to go, we’re three points ahead with a superior goal difference [United’s is plus 52; Chelsea’s plus 37], and if you’d offered me that at the start of the season I’d have snapped your hand off.

“The important thing is that our next two league games are at home [against Sheffield United and Middlesbrough]. It could go down to the wire, I suppose, and if it means us winning our last match, at home to West Ham, we’ll take that.”