BARCELONA (Reuters) - Nine-times European champions Real Madrid are likely to be without leading striker Ruud van Nistelrooy as they look to overturn a 2-1 first-leg deficit against AS Roma at the Bernabeu on Wednesday.
The Dutch international has been struggling with an ankle injury and coach Bernd Schuster said he was "almost certain" to miss out against the Italians in the Champions League first knockout round clash.
With fellow countryman Arjen Robben also missing out, the onus will be on Brazilian forward Robinho and Champions League record scorer Raul to prise open the Roma defence.
Chelsea look to have rediscovered their firepower up front at just the right time as they try to overcome Olympiakos in a tie that was locked at 0-0 after the first leg.
Avram Grant's side racked up a confident 4-0 victory over West Ham United on Saturday to raise morale after their defeat against Tottenham Hotspur in the League Cup final.
Olympiakos's hopes of making it through have been hit by the loss of former striker Lomana LuaLua, who dislocated his shoulder at the weekend in a 1-1 draw with Asteras Tripolis.
The Londoners have kept a clean sheet in their last five Champions League games, while Olymiakos have lost by at least two goals on each of their previous seven visits to England.
Porto will be hoping their impressive home record will help them turn the tables on Schalke 04 after a 1-0 defeat in the first leg in Germany.
The 2004 champions have lost only one of their last 19 home games in the competition, while Schalke, who have never made it into the quarter-finals, have gone off the boil recently and suffered a loss of form in the Bundesliga.
Reporting by Simon Baskett, editing by Miles Evans