Jose Mourinho has left Antonio Valencia out of group opener for one major concern

Antonio Valencia might be Manchester United's first-choice right-back but he will play no part of Wednesday's Champions League group opener.

Valencia has been left out of the matchday squad ahead of United's trip to Young Boys and there's a very specific reason for his omission. Red Devils boss Jose Mourinho insists that Valencia's track record of knee injuries concerned him as he prepared his side for the clash on the Swiss champions' artificial playing surface. "We decide not to play Antonio Valencia because his knee is not a knee that needs an artificial pitch at all," Mourinho said at the Stade de Suisse. "So we brought Luke Shaw back to the squad and to the team. I told already Luke Shaw is playing tomorrow and apart from him we have Diogo, Ashley Young and Darmian ready to play. "Valencia's situation, we need to protect his clinical situation, apart from that we go with everything we have and have to try and win." Valencia, who is United's club captain, played 92 minutes of his side's 2-1 victory over Watford on Saturday evening but the 33-year-old is at a point in his career where he cannot start every game. The possibility of losing the Ecuadorian full-back to a recurrence of his knee issues on Young Boys' controversial synthetic surface was too great a worry for Mourinho to risk him in the Group H match. "I think we are improving," Mourinho said after securing back-to-back Premier League victories. "We found a certain balance in the team, especially in the competitive attitude, we are creating lots of chances, changing our profile of play, the way we attack opponents, and we find a way to protect ourselves in some specific situations and we manage to get six points after two defeats which is important for us. "I'm happy but you know I was happy after the Tottenham defeat, not with the result but with many things I saw and we felt that match was okay, was the beginning of our improvement. And we managed that in two difficult matches away and let's see in our third match if we can win all of them."