Marcus Rashford was substituted despite a positive display at Porto Marcus Rashford was substituted despite a positive display at Porto 
Erik ten Hag has insisted Marcus Rashford's half-time withdrawal during Manchester United's draw with Porto was down to a need for rotation, not a statement on his performance. (More Sports News)
United are still searching for their first Europa League win of the campaign, after Harry Maguire's late header salvaged a 3-3 draw in Porto on Thursday.
After the Red Devils went 2-0 up through early goals from Rashford and Rasmus Hojlund, a strike from Pepe and a brace from Samu Omorodion had put them on the brink of another humiliating defeat.
To cap United's frustrations, captain Bruno Fernandes was shown a red card for a second successive game after also being dismissed in Sunday's 3-0 loss to Tottenham, having never previously been sent off in any of his first 241 games for United.
It was the decision to substitute Rashford for Alejandro Garnacho, though, that dominated post-match talk, with no United player matching Rashford's eight touches in the Porto box or three successful dribbles all game, despite his early withdrawal.
Speaking to TNT Sports after the game, Ten Hag said: "We have to rotate. Garnacho, we didn't start him, but he had a great game not only Sunday but the whole season.
"We go quickly with a turnaround to Villa and they have had a day longer to recover and we have an away game."
Rashford now has 14 goals in the Europa League, moving him outright fourth in the all-time UEFA Cup/Europa League charts among English players, behind only Martin Chivers (22), Alan Shearer (21) and Jermain Defoe (19).
Asked about the substitution again in his post-match press conference, Ten Hag added: "Yeah, but Garnacho was my best player on Sunday by far and also in many other games.
"I think in the season, as I assess it so far, he is bringing us so far the offensive threat by creating chances, assists, also scoring.
"Garnacho we also have to play as well and we have two very good players over that side."
Pushed on whether the decision had anything to do with Rashford's role in Porto's first goal, which came down the England man's flank, Ten Hag said: "I have to watch it back and I think over the left side definitely we didn't defend well tonight.
"Marcus also played a part in this but, as I saymr pacho, it had to do with Garnacho and nothing against Rashy."