London: Manchester United will enjoy the welcome distraction of Champions League football this week, taking on Greek side Olympiakos in the round of 16.
It has been a difficult season domestically with sixth-placed United knowing that qualification next year for Europe's elite club competition only looks possible through winning it this year. United performed impressively in the group stage, beating Bayer Leverkusen 5-0 away. Also Tuesday, last year's runner-up Borussia Dortmund travels to Russia to play Zenit St. Petersburg.
On Wednesday, Didier Drogba plays his former club Chelsea in Istanbul, as Galatasaray hosts the 2012 winner, and Real Madrid plays Schalke in Germany.
Here are four things to know about this week's round of 16 first leg action:
OLYMPIAKOS vs. MANCHESTER UNITED
Wayne Rooney, who has signed a contract extension to 2019, is set to lead United's charge at Olympiakos on Tuesday.
"Everybody wants to win it and we'll try to do it," United manager David Moyes said. "Teams don't want to play Manchester United. I hope we can play well enough to get through this round and see what happens next."
January signing Juan Mata is not available, having already featured for Chelsea in the competition but teenage midfielder Adnan Januzaj provides an alternative. Marouane Fellaini, who had been out injured since December, returned from injury in a 2-0 win against Crystal Palace on Saturday and could play.
Olympiakos beat OFI 4-0 on Saturday but striker Marko Scepovic, who scored a hat trick, is ineligible and fellow striker Javier Saviola was substituted after 33 minutes with an injured left thigh and misses the game.
ZENIT ST. PETERSBURG vs. BORUSSIA DORTMUND
Last year's runner-up Borussia Dortmund has its first ever meeting on Tuesday with Zenit St. Petersburg on the back of a 3-0 loss against second-from-bottom Hamburg.
Midfielder Nuri Sahin dismissed claims that the defeat could have an adverse impact on the team.
"We won our very difficult Champions League group (with Marseille, Napoli and Arsenal) so we can approach the last-16 stage with confidence," Sahin said. "This defeat against Hamburg doesn't change a thing."
But Dortmund is without Sven Bender, ruled out for 10 weeks with a groin injury while Mats Hummels is a doubt with a right-foot strain.
Zenit qualified for the knockout stage in second place in Group G but were some 10 points behind winner Atletico Madrid. They won 2-0 in a friendly on the weekend, with the Russian Premier League on a winter break.
GALATASARAY vs. CHELSEA
Chelsea goes to Istanbul to take on Galatasaray after retaining its position at the top of the Premier League with a 1-0 win against Everton.
Defender John Terry, who scored the winner in the third minute of stoppage time, will be looking to nullify the threat of former teammate Didier Drogba in the first leg on Wednesday.
Drogba is highly regarded by Chelsea fans, having scored the penalty that won the Blues their first ever Champions League title in 2012 with his last kick for the club.
Galatasaray also won 1-0 at the weekend against rival Besiktas, thanks to a penalty from midfielder Selcuk Inan.
SCHALKE vs. REAL MADRID
Schalke coach Jens Keller believes the odds are stacked firmly against his team being able to knock Real Madrid out of the competition.
"We'll need a little miracle," Keller said. "It'll be difficult but we're not going into it to exchange jerseys."
They drew 0-0 at home to Mainz on Friday, while Madrid won 3-0 against Elche thanks to goals from Asier Illarramendi, Gareth Bale and Isco.
Despite the difference in fortune for the teams going into Wednesday's game, Madrid's Bale is aware that Schalke will be difficult opponents.
"We know that the Champions League is a very tough competition," Bale said. "We are ready, prepared and we believe that we can beat any rival. We are going to Germany determined to win and expect to do so."