Ralf Rangnick insists subbing off Cristiano Ronaldo was the "right decision" as his side won 3-1 at Brentford.
The interim Manchester United boss switched to a back five as he looked to see out the clash with the forward the one to be sacrificed.
The Portuguese star was hauled off after 70 minutes in west London.
Ronaldo missed the last two games, both against Aston Villa, through injury but was keen to remain on the pitch.
He could be seen muttering as he walked off the pitch before continuing his rant on the bench.
Rangnick eventually had to go over to the 36-year-old and appeared to explain his decision.
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Rangnick told BT Sport: "That is normal - a striker wants to score - but he has come back from a little injury and it was important to remember we have got another game coming up.
He then added: "Also after what happened at Villa Park, we had to defend the lead this time and it was important that we went back to a back five and while we didn't keep the clean sheet it was important to make sure nothing else happened."
Rangnick later sent a direct message to Ronaldo as he told BBC Sport: "Listen Cristiano, you are 36 in great shape, but when are a head coach, you will see if through the glasses of a head coach.
"My job is to take the decisions in the best interest of the team and the club and I hope he sees it the same way."
The interim boss also hailed Elanga's performance with the teenager looking for regular football.
"Anthony Elanga followed up on the performance he showed at Villa Park," said the German.
"He was outstanding in the second half, put in a lot of work against the ball and then scoring the first goal. But I am happy for all our young players tonight - three young English goal scorers."
Ronaldo was replaced with United 2-0 up thanks to goals from Anthony Elanga and Mason Greenwood.
Marcus Rashford, who appeared off the bench, made it three before the Bees grabbed a late consolation.
The three points keeps the Red Devils firmly in the hunt for fourth place.
Ronaldo's last goal came in the 3-1 win over Burnley back on December 30.
United's No 7 claimed this week he plans to play on for several more years having long looked after his physique.
He said: "I still have the passion for the game. Not just to score goals, but to entertain myself because I played football since I was five or five or six years old.
"When I get on the pitch, even in training, I still enjoy it. My motivation is still there, even though I'm gonna be 37 soon.
"People ask me sometimes how many more years I'm going to play and I say, 'I hope to play four or five more years'."
United's next game is against top four rivals West Ham at Old Trafford.
