Henrik Larsson struck his 40th goal of the season 12 minutes from time to put Celtic into the final of the UEFA Cup with a dramatic victory over Boavista in the Bessa Stadium.

Martin O'Neill's men knew they had to produce the magic of Anfield to make their first European final since 1970, but time looked to be running down on their dream.

But despite missing a glorious first-half opportunity, the Swedish international once again saved the day with a cool finish to send them on the way to Seville on May 21.

It was all the more satisfying after Boavista boasted Celtic had no chance - but they proved again that it is dangerous to write them off with another away goal in Europe.

After scoring in Celta Vigo, Stuttgart, Liverpool and Blackburn, it was Larsson who continued their impressive run and end the league misery suffered at Hearts on Saturday.

But goalkeeper Robert Douglas was also heroic, after a couple of fine saves, along with striker Chris Sutton who came on early for Paul Lambert despite not playing since breaking his wrist in the CIS Insurance Cup final.

Celtic were left flying the flag for Britain after Manchester United's Champions League exit last night, but both sides started nervously with so much at stake.

But it was the visitors who settled down quicker and Larsson squandered a glorious chance to grab Celtic a crucial away goal in the ninth minute.

John Hartson flicked on Alan Thompson's free-kick and Larsson reacted quicker than the sluggish Boavista defence, but he failed to realise how much time he had and flicked his right-foot shot well wide from the edge of the box with just Ricardo to beat.

As predicted by O'Neill, Boavista started their play acting when Pedro Santos went down in agony after a fair challenge from Didier Agathe, only to fully recover moments later.

Celtic were looking for a strong referee in Russian Valentin Ivanov and he waved on the physios moments later after a crunching tackle between Paul Lambert and Silva.

Defender Avalos was the next man to go down theatrically after a clash with Neil Lennon, but justice was done when Pedrosa fired high over the bar from 25 yards.

The Boavista player again ambitiously chose to go for goal with his next free-kick, but again blasted into the netting behind the goal.

Pedrosa was again off target from well outside the box after Johan Mjallby had dangerously given the ball away in his own half.

The officials failed to spot a late challenge from Silva on Balde, but the defender's reaction to get to his feet immediately took the sting out of the incident.

Boavista's first real threat came in the 33rd minute, when hesitancy from Douglas made the situation a lot worse than it should have been.

Martelinho found Santos down the right and he fired across the face of goal, but despite no team-mates in support, Mjallby had to head the ball away.

But a minute later, Celtic suffered a blow when Lambert was forced hobble off after the earlier collision with Silva and Sutton came on much earlier than he expected.

Boavista seemed to grow in confidence from that and Santos' 20-yard right-foot strike curled wide of Douglas' upright from Duda's pass on 37 minutes.

But the Scot denied the home side the opener just two minutes before the break when Silva got on the end of Martelino's cross, but the keeper did well to push his header away.

Celtic came out for the second half much more urgently as they chased the away goal and Ricardo again flapped at a long Joos Valgaeren throw-in, but again survived.

Filipe Anunciacao got away with a blatant hand-ball in the 52nd minute, but Duda wasted possession with the visitors short of numbers at the back.

Valgaeren almost got on the end of Hartson's ball on 55th minutes, but Pedrosa made a vital challenge to stop the Belgium a clear route on goal.

But at the other end, Celtic should have found themselves behind on the hour mark, but for another great save from Douglas.

Douglas misjudged Duda's cross and could only touch it into the path of Santos, but made amends to tip the Brazilian's effort around the post.

Celtic were desperate for Agathe to get away down the right, but he harshly became the first player booked for a foul moments later.

The home side brought on Luiz Claudio for Silva in the 70th minute and he almost got on the end of Martelinho's cross, but for Douglas' awareness to cut the ball out.

Celtic's desperation grew as the clock ticked away and Thompson had the fans off their seats, but his fierce long-range drive flew wide.

Avalos was deservedly booked for a reckless foul from behind on Larsson in the 75th minute before O'Neill sacrificed Valgaeren for an attacker in Jamie Smith.

And the Northern Irishman's bold move paid off in the 79th minute when Larsson made up for his earlier miss to put Celtic ahead and grab them an away goal.

The Swede had fortune on his side as Sutton's intended pass broke off the defender into his path and he slotted the ball past Ricardo, who got a hand to it, but could not keep it out.

Celtic breathed a sigh of relief in the 86th minute when Jocivalter went down theatrically in the box under the challenge of Agathe.

But referee Ivanov waved play on before sparking wild celebrations with his full-time whistle as Boavista were denied an all-Porto final in Seville.

Teams

Boavista: Ricardo, Mario Loja, Avalos, Eder, Erivan (Jocivalter 80), Anunciacao, Martelinho, Pedrosa (Yuri 84), Pedro Santos, Silva (Luiz Claudio 68), Duda.

Subs Not Used: William, Rui Oscar, Bosingwa, Goulart.

Booked: Avalos.

Celtic: Douglas, Valgaeren (Smith 75), Balde, Mjallby, Agathe, Lennon, Petrov, Lambert (Sutton 34), Thompson, Larsson, Hartson.

Subs Not Used: Marshall, Sylla, McNamara, Laursen, Maloney.

Booked: Agathe, Mjallby.

Goals: Larsson 80.

Agg (1-2)

Att: 11,000

Ref: Valentin Ivanov (Russia).