VIGO, Spain, Dec 12 (Reuters) - John Hartson's vital away goal ensured Celtic clinched a place in the UEFA Cup fourth round despite losing 2-1 at Spanish side Celta Vigo on Thursday.

The Scottish champions progress in Europe beyond Christmas for the first time in 23 years even though Benni McCarthy lashed home a second-half winner for Vigo in the third-round match after Celtic had won the first leg 1-0 in Glasgow.

Jesuli gave Vigo an early lead before Hartson grabbed his all-important goal for Celtic before half-time.

South African striker McCarthy scored for Vigo - who are third in the Spanish league - on 53 minutes, but Celtic put on a brave defensive display to deny the home side a third goal.

Celtic had to contend with some dreadful decisions by Danish referee Claus Bo-Larsen - and constant unsporting behaviour from the home players - as they eliminated a Spanish side from Europe for the first time in their history.

'It's been a magnificent effort from the team and we're delighted that a lot of our fans, who have paid hard-earned money before Christmas, have come over to see it,' Celtic manager Martin O'Neill told reporters.

'They're sitting third in the Spanish league and they can play, but we've soaked up a lot of pressure to deservedly go through.

'The team has a number of qualities that showed out there. We've got a great desire and a willingness to go through the pain barrier. They've an enormous spirit about them.'

INTELLIGENT PLAY

Vigo looked like they would overhaul Celtic's advantage in the first period with Argentine winger Gustavo Lopez causing Joos Valgaeren no shortage of problems.

Scotland keeper Robert Douglas did well to scramble a shot from Jesuli round the post after some intelligent play by McCarthy before the same pair combined to give Vigo the lead on 22 minutes.

McCarthy again fed Jesuli, whose shot deflected off Ulrik Laursen to fly past the helpless Douglas.

Vigo were cutting Celtic open with some piercing attacks, but the visitors fought back and Jose Pinto made alert saves from Stilian Petrov and Neil Lennon within a few minutes.

Celtic then got the vital away goal on 36 minutes as Welsh striker Hartson used strength on the edge of the box to wallop home the equaliser with a blistering effort.

Vigo now required two goals to progress to the next round and they got one of them thanks to McCarthy.

With Celtic temporarily reduced to ten men due to a hamstring injury to Lennon, Lopez displayed some lovely skill to cross for McCarthy to score.

Jesuli squandered a glorious effort moments later to net another for Vigo and that was a close as they were to come with Scotland player Jackie McNamara coming on as a substitute to help nullify the threat of Lopez in a four-man defence.

Celta never seriously troubled in the final half hour and Spanish international Juan Fran should have been sent off after aiming a kick at Bobo Balde in the first half and slapping McNamara's face towards the end of the match.

'We got tired in the second half, but we had to defend what we had and we did that magnificently,' added O'Neill.

'We've knocked out a top Spanish side and we'll look forward to playing in the last 16 when it comes round.'