SOCCER/Blackburn 1 Chelsea 2 After extra time. 1-1 after 90 minutes:  The season is coming to a close yet for Chelsea it must feel as if there is an infinity of football before them. That is no reason for distress when a game such as this FA Cup semi-final can bring them so fierce a joy. They negotiated this odyssey of an afternoon and found a course to their destination, the meeting with Manchester United at the new Wembley on May 19th.

The fixture at Old Trafford showed all the qualities they possess, including the odd dash of luck. With seven minutes of normal time remaining, Morten Gamst Pedersen had a free header from David Bentley's cross and sent it wide. Even Chelsea might not have come through then as their energy was ebbing away.

They were dishevelled and in the 89th minute John Terry misheaded Pedersen's throw-in, only to be redeemed by an uncanny save by Petr Cech as he clawed the ball away. No physiologist could explain fully how Chelsea recharged themselves after that, but it was Blackburn who were eventually made to look as if they dreamed purely of a penalty shoot-out.

The Stamford Bridge team would not permit them to get there. Four minutes into the second period of extra-time, one substitute, Salomon Kalou, found another in Shaun Wright-Phillips. The winger turned Ryan Nelsen on the byline and while Kalou could not convert the low cross the ball ran into the path of Michael Ballack who drilled home a left-footer.

Influential substitutes certainly help Chelsea to weather the storms of this campaign, but the phases in the individual form of those who generally start games appear to mesh importantly as well.

Ballack, who has sometimes looked like a journeyman of a galactico, had a lot to contribute in the semi-final.

With 16 minutes gone, Cech kicked downfield, Didier Drogba chested the ball off tidily and the German rolled an impeccable pass. Frank Lampard's touch was ideal as he guided it away from the lunging Nelsen and angled a shot past Brad Friedel.

Despite that breakthrough, the fixture lasted so long that it became a survey of every incarnation of Chelsea. For much of the first half they performed quite beautifully, giving the lie to anyone who argues that they are no more than pragmatists. The only flaw lay in the faulty finishing. Ashley Cole and Drogba, for instance, set up Joe Cole in the 22nd minute, but having juggled the ball from left foot to right he then lofted it high.

That was one of the scarce indications that the midfielder, because of injury, had not started a game for five months. His contribution in Valencia had mattered as well, but even Chelsea's most loyal follower must have feared they would flag as Blackburn pounded them for a while.

Jose Mourinho kept a low profile yesterday instead of imploring his men from the outer limits of the technical area. If that was unexpected then so, too, was the sight of the Chelsea team sitting on the turf at the end of 90 minutes. The orthodox interpretation would regard that as a sign of weakness, but Blackburn had been seriously misled if they came to that conclusion.

Very few sides with the effects of so many fixtures in their legs would have outlasted Mark Hughes's team. Chelsea's initial ascendancy came to a close after 47 minutes as Drogba squared and the hapless Andriy Shevchenko miskicked so comprehensively that the ball flew sideways when he was expected to score.

Blackburn reacted by unleashing all their verve and determination and Pedersen headed against the post in the 61st minute. Two minutes later the Norwegian relished a free-kick on the right. His menace there always inspires a murmur of anticipation and a whip of his left foot put the ball towards the near post where Jason Roberts, in front of Terry, slipped a low shot home.

The pause at the close of normal time came as a relief to Chelsea and they somehow found enough recuperation there.

Drogba had been dominant at the start and, by the close, it was the last line of defence, Cech, who was indispensable.

From one end of the team to the other Chelsea are astonishing.

Guardian Service