Lionel Messi during a practice session

London: The clash between European nobles Barcelona and AC Milan looks the only wide-open Champions League quarter final second leg this week with Real Madrid and Bayern Munich all but through and Chelsea in good shape.

Most eyes are therefore focused on the Nou Camp where Barca — lauded by many pundits as the greatest club side of all — take on seven-time European champions Milan.

Barca and Lionel Messi can write new chapters in the record books if they are able to break out of the straightjacket imposed on them by Milan and reach the semi-finals.

Milan held Barca to a rare 0-0 draw in their quarter final first leg at the San Siro last week, their rugged defence denying the in-form Messi a goal with some well-organised harrying and hustling.

Holders Barca are bidding to become the first team to win consecutive Champions League titles and a fifth semi-final appearance in a row would match the record set by arch-rivals Real Madrid between 1956 and 1960.

World Player of the Year Messi needs one more goal to break the Champions League season record of 12 goals, set by himself last season and Ruud van Nistelrooy in 2003 and also notch up his 50th goal of the competition.

The Argentine netted his 56th goal of the season from the penalty spot as Barca overcame Athletic Bilbao 2-0 at home on Saturday, keeping them six points behind leaders Real Madrid in La Liga.

Barca have not lost at home in Europe since 2009 while Milan have yet to win away this season in the Champions League but did grab a 2-2 draw at the Nou Camp in the group stage in September.

A repeat in Tuesday’s last-eight second leg would put the Italians through. “Milan have great players, they are a great team and they will make life very difficult,” Barca forward Pedro said.

Barca will at least be able to rely on their immaculate playing surface at the Nou Camp after posting an official complaint to Uefa over the poor state of the pitch in Milan last week.

Serie A leaders Milan drew 1-1 at Catania on Saturday and were aggrieved for a second time this season that a goal which seemed to have crossed the line was not awarded. Robinho was the man denied.

The Brazilian has been working his way back to full fitness and should again start although compatriot Alexandre Pato is in the frame again after having cured his injury.

Alessandro Nesta, who gave Messi a rough ride in the first leg, was rested against Catania because of a knock but the 36-year-old may return at the Nou Camp.

Barcelona, on the other hand, have a doubt over midfielder Xavi. The 32-year-old player has missed the last two training sessions. “His calf has been playing up for the last couple of days and we preferred not to force it today,” Guardiola said.

Meanwhile, Bayern will be highly confident of progressing on Tuesday against Olympique Marseille, having won the first leg 2-0 in France last week.

Marseille’s need a miracle to advance past Bayern Munich and into the Champions League semi-finals as they arrived exhausted in Munich after a six-hour delay due to a strike in France.

“We will have a lot of quality against us but at the end we do not want to regret anything and we will see what comes out of it,” coach Didier Deschamps said. “The chances are minimal.”