Manchester United faces Champions League exit . The Premier League's top four clubs are all in the Europa League, with Arsenal and Chelsea also playing at home to German opposition. Christian Karembeu backs Greek side 's chances . United unlikely to qualify for next year 's competition .
Manchester United faces Champions League exit . Olympiakos takes 2-0 lead to Old Trafford Wednesday . Christian Karembeu backs Greek side 's chances . United unlikely to qualify for next year 's competition .