Goals: Xavi 3'

Xavi Hernandez's goal in the opening exchanges eased 2006 winners Barcelona into the Champions League quarter-finals with a 1-0 win over Celtic here on Tuesday.

After the Spanish giants' 3-2 win in the first leg in Glasgow a fortnight ago, Xavi ended Celtic's dreams of an upset after just three minutes to leave Barcelona 4-2 winners on aggregate.

"We started well and got a goal at an important moment but after that Celtic recovered and gave us a hard time," commented Barcelona coach Frank Rijkaard.

Barcelona's opener came as a result of a stunning combination which showed off their players' mutual understanding at its best.

Ronaldinho, standing on the edge of the area, flicked across a pass to his left while looking in the other direction and his compatriot Sylvinho picked up the ball and headed down the flank before crossing to Xavi.

The Spanish international playmaker then volleyed the ball over the head of Celtic's Polish goalkeeper Artur Boruc to take the midfielder's tally to a remarkable five goals in his last seven matches.

"We had a plan and part of that deal was tackling and we didn't do that," reflected Celtic coach Gordon Strachan on the Xavi goal.

"At least we consolidated after that and didn't concede any more."

Xavi's strike seemed to take the wind out of the sails of the Scottish side, perhaps conscious of the fact that getting three goals without reply in the Nou Camp was an almost unobtainable target.

Barca could have added to their tally in the following minutes when Ronaldinho and Samuel Eto'o both went close.

By contrast, Celtic were unable to launch an attack of any real significance before the break but, with nothing to lose, they pressed forward in a more committed fashion at the start of the second half.

"I don't think that the first leg was a true reflection of what these players can do as individuals but I think I got many good performances from players tonight," commented Strachan.

"I felt a wee bit better about our performance the longer the game went on. I think they gave a good account of themselves in the second half. They freed themselves from worry. There were not too many chances but there were chances," added the Celtic coach.

Second half substitute Georgios Samaras, who came on after 55 minutes for a clearly not fully fit Jan Vennegoor of Hesselink, presented the first moment of real danger by Celtic just after coming on the pitch.

The Greek striker got behind his marker Lilian Thuram but Barcelona captain Carles Puyol was on hand to thwart him and partially make up for his errors in Saturday's 4-2 loss at Atletico Madrid, their first defeat of the year.

At the other end, Barcelona continued to keep Boruc and the Celtic defenders occupied without ever needing to get out of second gear.

On the hour, Deco unleashed a rasping volley from 20 metres out that required an outstanding diving save from Boruc to avoid the Portuguese player scoring while Eto'o missed a sitter after 72 minutes.

One sad note on the night for Rijkaard was another injury to his often-inspirational Argentine winger Lionel Messi.

"Messi's injury has over-shadowed the night. It has affected everybody," said Rijkaard.

Messi, who has been suffering from various aches and strains in recent weeks, pulled up with a left thigh problem while going for the ball and limped off in tears after 34 minutes.

The initial diagnosis given by the Barcelona doctors was of a torn muscle in which could keep Messi, the 2007 World Player of the Year runner up, out of action for a month, which would mean he could miss at least the first leg of Barcelona's quarter-final encounter.

"All we can do is wait for the tests tomorrow (Wednesday) and hope it's not as bad as it looks right now. He's suffering, he's not feeling well. It's a hard situation," added the glum-looking Barcelona coach.

Barcelona: Valdés; Zambrotta, Thuram, Puyol, Sylvinho; Touré (Edmilson 67'), Xavi (Gudjohnsen 81'), Deco; Messi (Henry 38'), Ronaldinho, Eto'o.

Celtic Glasgow: Boruc; Wilson, Caldwell, McManus, Naylor; Nakamura, Brown, Hartley (McDonald 79'), Donati (Sno 45'), McGeady, Vennegoor of Hesselink (Samaras 56').