Winning the Champions League has never been more important for Manchester United. Just to get a chance to rejoin Europe's elite again.
With United in an unusually low English Premier League position, 11 points from the fourth Champions League place, qualifying for next season's Champions League through the usual domestic route seems unlikely.
"As a group of players we have to take responsibility for our league position," United striker Wayne Rooney said. "We know we're better than that and we haven't performed as well as we can do. It hurts."
So David Moyes' side wants to build a strong first-leg lead at Olympiakos on Tuesday to smooth the passage to the quarterfinals. And beyond, given how essential winning the May final is to the club's pride and global standings.
Here are five things to know about Tuesday's round of 16 game in Greece:
RESPITE IN EUROPE: If only United's European form had been replicated domestically, it wouldn't be so bleak for Moyes during his first season in charge. In the Premier League, United is meekly surrendering the trophy, sitting in sixth place, ahead of Everton only on goal difference and having played an extra game. But United eased through the Champions League group stage with four wins, including an eye-catching 5-0 rout at Bayer Leverkusen, and two draws. Going through as group winner ensured the three-time European champion avoided potentially trickier teams at the start of the knockout phase. "We know Manchester United are not allowed to make any mistakes due to their position in the Premier League and we have to say probably this kind of situation may weigh too much on their players' shoulders," Olympiakos manager Michel said. "It could be an incentive to them or it could be a burden on their shoulders."
CONSTRASTING FORM: While it's miserable for United domestically, Olympiakos is unstoppable, sitting 23 points clear at the top of the Greek Super League. Just nine goals have been conceded in 26 unbeaten games. "Olympiakos came through a difficult group with Benfica, Paris Saint-Germain (and Anderlecht)," Moyes said. "They have a great home record so it will be a difficult night."
STOPPING THE STRIKERS: Olympiakos has lost all four previous encounters with United, and any chance of a reversal in fortunes hinges on stopping strikers Robin van Persie and Rooney. Both scored on Saturday as United ended a three-match winless run in the league by beating Crystal Palace 2-0. "We've got a good record when we've played together but unfortunately we have had injuries at similar times but hopefully we can stay fit and help us win games," Rooney said. He travels to Greece with his future settled, having signed a lucrative new United deal through 2019 on Friday.
STRIKER SHORTAGE: Where will Olympiakos' goals come from? Michael Olaitan is the only fully fit striker, with doubts about Nelson Valdez's fitness. Top scorer Javier Saviola has already been ruled out of the game with a thigh he injured in the 4-0 win at OFI Crete on Saturday, fellow striker Marko Scepovic is cup-tied, while Konstantinos Mitroglou joined Fulham last month. "Mitroglou was a really good goal-scorer for them and a main player," Moyes said. "Does it weaken them? They'd rather have him than not but probably felt the offer was so good they had to take it."
RACISM IN THE STANDS: UEFA will be keeping a close eye on the Olympiakos supporters after racist behavior by some during the final group stage match against Anderlecht led to UEFA sanctions. The lower tier of the north stand at Karaiskakis Stadium will be closed as punishment, and further racism could lead to the entire stadium being closed to fans for the next UEFA fixture. "We hope it'll be a lesson not just for us but for everyone in football, to show that you shouldn't bring non-football things into a football match," Michel said. "Of course, we'd rather have all our fans tomorrow night, which would mean we'd made no mistakes and would have more people cheering for us, but it shows we have respect for the rules."