Lisandro Lopez (left) and Jorge Fucile of FC Porto during a training session at the Dragao Stadium in Porto on Tuesday. (AP)

London: Real Madrid and Chelsea could each need just one goal to reach the quarter finals of the Champions League on Wednesday.

Madrid trail AS Roma 1-2 after the first leg two weeks ago, so a single goal and a clean sheet at the Santiago Bernabeu would send the record nine-time European champions through to the next round.

Chelsea are in a similar situation when they host Olympiakos after a scoreless draw in Greece, but the odds are better for Chelsea than Madrid.

Madrid’s recent form indicates that they will probably need to score more than one goal. Despite reclaiming a five-point lead in the Spanish league at the weekend, the 3-2 win at Recreativo Huelva again exposed Madrid’s weakness at the back, which won’t be helped by the absence of defender Christoph Metzelder because of injury.

Roma showed in the first game at Stadio Olimpico that they know how to exploit that weakness, with David Pizarro and Amantini Mancini scoring after Raul Gonzalez had given the Spanish team an eighth-minute lead.

Real defender Fernando Gago will be marshalling the defence with Sergio Ramos suspended.

The options up front look slightly better, even after winger Arjen Robben was ruled out for six weeks on Monday because of a sprained ankle.

Madrid are pinning their hopes on the return of Robinho and a flawless display in defence. He could start in place of Ruud van Nistelrooy, who is carrying a sore ankle.

Roma issued a clear warning of their attacking power by thrashing Parma 4-0 on Saturday.

Striker Francesco Totti, who is returning to his best after a back problem and scored a fine strike against Parma, is taking heart from the memory of a goal that gave Roma a 1-0 group-stage win in the competition at the Bernabeu in October 2002.

“I have already scored a historic goal at the Bernabeu and I hope to score another,” he told reporters. “Roma just need to play as they know how to. If we are concentrated we'll be able to have our say.”

Full-back Marco Cassetti is out with a shoulder injury, Juan is battling to return to fitness from a foot injury and David Pizarro is also a doubt.

Chelsea are looking strong on the field after a 4-0 win at West Ham in the English Premier League, but British papers have reported disharmony in the Blues squad, which will improve the Greek team’s hopes of a shock win.

Olympiakos will be without striker Lomana LuaLua because of a dislocated shoulder. LuaLua will be joined on the sidelines by Argentine winger Luciano Galletti who has a thigh strain.

Chelsea’s problems seem to stem from an inability to fit all their stars into a single team. Several players are reportedly unhappy at coach Avram Grant’s seeming preference for the likes of John Terry and Frank Lampard over in-form defender Alex and Germany captain Michael Ballack.

With progress to the next round essential, Grant could stick with largely the same team that beat West Ham, although Didier Drogba could replace Nicolas Anelka up front.

With Liverpool’s return match at Inter Milan postponed until next week, Schalke’s visit to 2004 champion FC Porto is the only other game on Wednesday. Schalke lead 1-0 after Kevin Kuranyi scored in the first leg.