Pep Guardiola  has rated the second leg of the Champions League  quarter-finals at Manchester United  as a matter of life and death. A week has once again proven to be a long time in football has both Bayern Munich  and Manchester United come into the encounter with contrasting fortunes. Ahead of the first leg, Bayern came in with an unbeaten run that stretched over 50 matches. United, on the other hand, came on the back of heavy defeats against Liverpool and Manchester City.The second leg, though, will see form reversal after Bayern suffered their first defeat in the league this campaign. Their unbeaten record is gone, and there is now an air of vulnerability surrounding the German champions that did not seem to exist a week ago. According to Sky Sports, Guardiola said:"It's a final, a life or death match. United will be looking to hit us on the break and at set-plays and we have to be aware of that."They are one of the best teams in the world, but our away goal is very important even though 1-1 can be very dangerous."Guardiola knows that he is trying to live up to a huge achievement since he has to win more than three trophies in order to better last season’s performance. In such circumstances, league victories and Super Cup wins alone will not be helpful. Guardiola has to guide Bayern Munich to Champions League success, which would also make the German outfit the first to defend the competition. Hence, it is understandable to see Guardiola taking the United match seriously.David Moyes appeared to be on the verge of losing the faith of the supporters a few weeks ago. However, United are looking to be at their devastating best under Moyes, as they thrashed a poor Newcastle United team 4-0 during the weekend. Wednesday will present a much tougher opposition, while Moyes will also be without Juan Mata, who is finding his best form with United.Defender Jerome Boateng also spoke about the importance of the match. He said:"I've got a few butterflies in my stomach. It's like a final and we've got to play to win because we will end up losing if we play for a goalless draw."We've got be aggressive going forward from the start and try to score. United will sit back again, but they'll take more risks the longer the game goes on.”United need to score in order to go through, and right now, it does not seem beyond the possibilities.