MANCHESTER (Reuters) - Manchester United should be "embarrassed" at trailing Premier League leaders Chelsea by 19 points and Jose Mourinho's first year in charge will not be considered a success even if they win the Europa League, former skipper Roy Keane said.

Mourinho steered United to League Cup success in February but with the club unlikely to finish in the top four it appears they will need to win the Europa League if they are to secure a Champions League berth next season.

United hold a 1-0 advantage from the first leg against Celta Vigo, who they host later on Thursday.

"For a club like Man United to win the League Cup and the Europa League, with the teams that are in it, you would expect them to do that," Keane told ITV.

"He (Mourinho) has come up with plenty of excuses over the last few months, but there is no reason why United should shy away from dealing with these challenges.

"They are now sixth in the league, I think they are 19 points behind Chelsea. The manager and the players should be embarrassed by that."

Keane also questioned the role of United skipper Wayne Rooney, who has struggled for playing time this season.

"Wayne needs to be playing regularly, to keep in shape and stay on top of his game," Keane added.

"If he is going to be a bit-part player at United then forget about it. He has got to move on."