It was a meek display from the hosts and a performance in stark contrast to the way they roared back to victory at the Etihad Stadium the previous weekend - a result of what Mourinho believes was over-confidence and complacency.

The United boss has now vowed to drop some big names ahead of Saturday's Wembley semi-final against Spurs, with changes also in mind for Wednesday's Premier League trip to Bournemouth.

"Rotating is not the right word," Mourinho said of his approach at the Vitality Stadium.

"If I play a player against Bournemouth and the player is phenomenal, he plays the semi-final.

"So is not rotating, because rotating looks like a player that plays against Bournemouth is to give a rest to somebody that is going to play against Spurs in the semi-final.

"So, the word is not rotation, it is an opportunity for people, for some people to play and to try to get a place in the team for Spurs - and some of the guys that played (against West Brom), they don't have a place in that team."

Asked to clarify if he meant that some of those who under-performed against West Brom would now not play against Tottenham, Mourinho retorted: "Yeah.

"What is the criteria for a manager to choose a team? I only know one criteria: the way you play is the only way I can select players.

"Or do you want me to go for the price they cost, or their salary, or their beautiful face? The only way is to go with performance."

Ander Herrera was replaced at half-time on Sunday and Ashley Young was taken off in the 75th minute, while Paul Pogba was withdrawn in the 58th minute.

The France midfielder was a shadow of the imposing, match-winning presence seen in the second half at the Etihad.

"It was not just him," Mourinho said of Pogba's performance.

"And he had a yellow card, so he was in a more difficult position than others.

"And playing with only two midfield players, you cannot play with one player in risk of not being able to make a foul.

"You can do it if your team is not losing the ball, but our team was losing the ball so easy with the complication, everything was complicated, so we were losing lots of balls.

"So, by losing lots of balls, with turnings and flicks and tricks, the midfield players and central defenders are at risk of one touch, one late challenge and they are out.

"So, Paul was out because of the yellow card, because in terms of the way he played he was not worse than some others that were on the pitch for 90 minutes."

Mourinho's disappointment will have no doubt been compounded by the fact some of those under-performing have been key players for him.

"Consistency has nothing to do with age," the United boss said when asked if he was getting the best out of the experienced, established players.

"It has to do with personality, has to do with the way you live for football, what is your priority in your life, your ambitions. It has not to do with age.

"I met players 30-years-old, not consistent at all, and I found boys of 18, 19, 20, real men, real pros, so it's not about the age."