Nemanja Vidic has urged Manchester United to develop a winning mentality within the squad, insisting that they must not accept a defeat, or even a draw, as being good enough.
And Vidic was not impressed with what he saw at Old Trafford, making it known that he wants to see the United players show more desire, energy and speed of movement.
He told Sky Sports: "Today they didn't show what we expected, the energy going forward, that burst or sprint. It was too slow, which was disappointing.
"That is my worry, I'd like to see United playing faster, quicker with the ball. It's too many touches, that's the problem, especially against smaller teams.
"They have a good team, good players, but sometimes I think the players have to show desire, show energy, run more than other teams.
"They didn't move well without the ball, they didn't move fast. The players didn't perform the way they wanted.
"It's sad to see Man United lose at home to West Brom, a team who have won just three games all season."
Vidic won five league titles during his time as a Manchester United player, as well as the Champions League in 2008, and the Serb emphasised how important it is to generate a winning mentality within the camp.
"It seems like he is saying there is a problem with mentality in the players. I think the Man United players know every game is important and they have to win.
"You play for Man United, it's not acceptable to draw or lose, always you have a high expectancy.
"We won the Champions League and we didn't celebrate. We had two hours of celebration, go on holiday, and the manager was thinking: 'Who will we bring in next season to compete?'"