With hopes of a top-four finish in the Premier League fading, Manchester United approaches Tuesday's Champions League last 16 first-leg match at Greek champion Olympiakos desperate for a positive result.

Not only does the competition represent United's last realistic hope of silverware this season - it may need to win the Champions League just to qualify for next season's tournament.

United is currently 11 points below Liverpool, which occupies the fourth and final Champions League place. With only 11 games remaining, qualification via the league might already be too difficult a task.

United has won only four of its 11 matches since the turn of the year, but the Champions League provides a respite from its domestic woes during the European autumn.

The three-time continental champion qualified comfortably as Group A winner, winning four and drawing two of its six matches and enjoying 4-2 and 5-0 victories over last year's runner-up, Bayer Leverkusen.

Nevertheless, with Arsenal and Manchester City having already lost their own last 16 first-leg matches, to Bayern Munich and Barcelona respectively, the tournament final in Lisbon on May 24 remains a long way off.

"Only one team can win it, and it's very hard," United striker Robin van Persie told Champions magazine.

"It's a trophy many players don't win; once, if you're very lucky. You have a couple of players who've won it more than once, but it's a very special trophy.

"It seems to get harder every year to win it, because the teams are getting better and better."

United warmed up for Tuesday's game at Karaiskakis Stadium in Piraeus by winning 2-0 at Crystal Palace in the Premier League on Saturday, with van Persie opening the scoring from the penalty spot.

Wayne Rooney doubled United's lead to mark his 300th league appearance for the club with a goal and celebrate his new five-year contract, which is reportedly worth $500,000 a week.

It was a rare straightforward afternoon for United manager David Moyes, who was able to start a game with Rooney, van Persie, Adnan Januzaj and record signing Juan Mata in his team for the first time.

Mata is cup-tied in the Champions League, but Moyes hopes to have defenders Rafael da Silva, Phil Jones and Jonny Evans available to face Olympiakos after the trio sat out the trip to Palace due to injury.

United is unbeaten against Greek teams and Olympiakos has not reached the Champions League quarterfinals since 1999, although it has won at home to Arsenal twice in the last two seasons.

The Greek giant can nonetheless take heart from its domestic form, having won 24 and drawn two of its opening 26 league games and reached the semifinals in the Greek Cup.

Saturday's 4-0 win at OFI Crete came at a cost, however, with experienced Argentine striker Javier Saviola forced off with a left thigh injury.