Liverpool and Arsenal have little time to recover from disappointing losses and prepare for the return of the Champions League.
Both lost in the fifth round of the FA Cup on Saturday _ Liverpool falling to lower-league club Barnsley 2-1 at Anfield and Arsenal routed by Manchester United 4-0. Both face Milan-based clubs in the first leg of the second round.
Liverpool, a five-time champion and runner-up last season, hosts Italian league leader Inter Milan on Tuesday.
The Champions League is realistically the only trophy Liverpool has left to play for after being ousted from both domestic cup competitions and trailing Premier League leader Arsenal by 19 points.
The last-minute loss to Barnsley hit Liverpool, and manager Rafa Benitez, hard.
"Frankly I am stunned and bitterly frustrated," said Benitez, who bemoaned his club's failure to take scoring chances. "You cannot blame any one player, but now we have to look to the next game against Inter. We have to concentrate on putting things right in the next match."
At least Arsenal can console itself with the five-point lead it has in the Premier League _ but its main rival in England is Man United, whose manager Alex Ferguson triumphantly claimed after Saturday's win that his side would soon make up the gap. The Gunners host defending champion AC Milan on Wednesday after finishing second to Sevilla in the group stage. Milan is fifth in the Serie A, 21 points behind Inter but has a strong European pedigree, having won the title seven times.
"The targets now in front are now are very clear _ it's the championship and the Champions League," Arsenal manager Arsene Wenger said. "We are not in a position where we need to make a choice. We need to pick ourselves up quickly because we have a massive game on Wednesday night."
Like Arsenal, AC Milan has been affected by injuries, with Ronaldo undergoing a knee operation last week and goalkeepers Zeljko Kalac and Dida in doubt. Kalac dislocated a finger on his right hand in training Sunday, while Dida has a back injury. If both are out, Valerio Fiori could play, but he hasn't played a competitive match since December 2003.
In Tuesday's other matches, it's: Olympiakos vs. Chelsea; AS Roma vs. Real Madrid; and Schalke vs. FC Porto. On Wednesday, it's: Celtic vs. FC Barcelona; Fenerbahce vs. Sevilla; and Lyon vs. Manchester United.
Real Madrid still leads the Spanish league but has had an inconsistent few weeks.
Sandwiched between away defeats was a 7-0 win over of Valladolid. A nine-point advantage at the top the league was cut to five on Saturday following a 2-1 loss to Real Betis.
"Tuesday's Champions League fixture against Roma will be a different game," Real Madrid coach Bernd Schuster said. "The match against Roma will be very important and my men will be much more motivated for it."
Injuries are taking their toll, however, with Robinho (stomach), Wesley Sneijder (fractured rib), Pepe (leg) and Christoph Metzelder (leg) all sidelined.
Forward Arjen Robben should get his first European start alongside Ruud van Nistelrooy, who was only used as a substitute Saturday.
Roma lost to Juventus 1-0 in the Serie A but is still in second place in the league.
Chelsea heads to Athens, Greece, with midfielder Frank Lampard and captain John Terry recovered from long-term injuries. Both played in the 3-1 FA Cup win over Huddersfield on Saturday, with Lampard scoring two goals and setting up the third. "They deserve to be the heroes of the club because of what they give to the team," Chelsea manager Avram Grant said. Grant warned Chelsea not to be complacent about the Greek champions.
"You may think this looks easy on paper, but it could be very difficult," Grant said. "We must not underestimate Olympiakos and their supporters are fanatical for the team."
Olympiakos coach Takis Lemonis has all his players fit for the match and is ready to prove his side deserves to be at this stage of the competition.
The club hasn't contested a knockout round match in nine years and won its first away match in 32 attempts when it beat Lazio 2-1 in the group stage.
"Chelsea are not the most spectacular team in Europe, truth be told, but they are strong in every aspect and very tough to beat," Lemonis said. "Chelsea are favorites, of course, but we are determined to put up a fight."
Schalke has one eye on the Bundesliga title, which it hasn't won since 1958, when it hosts 2004 champion and Portuguese league leader FC Porto.
It lost to VfL Wolfsburg 2-1 Friday, which leaves it in fourth place, eight points behind leader Bayern Munich.
"It's all the more disappointing that we were unable to extend our lead or at least hang on to it," Schalke coach Mirko Slomka said. "Unfortunately we have a habit of surrendering leads."