Jose Mourinho was strongly critical of Manchester United's attack in the absence of Romelu Lukaku after seeing his side slump to a 1-0 Premier League loss at Brighton and Hove Albion on Friday.
With Lukaku and Alexis Sanchez both sidelined due to injury, Anthony Martial and Marcus Rashford were given chances to impress in attack ahead of the FA Cup final.
But both forwards failed to make an impression, Rashford registering the only shot on target between them as a Pascal Gross header settled the match and secured Premier League survival for Brighton.
Mourinho, who has seen his side beaten by all three promoted sides in the Premier League this season, did not hold back in his criticism of United's front line.
"Not good enough. The players that replaced others, they didn't perform," the United manager told Sky Sports.
"When individuals don't perform at a good level it's difficult for the team to perform at a good level. Maybe now you understand why some players don't play more than others.
"I wouldn't say disappointed because I know them, but I thought for some of them the possibility to start the game, the possibility to give reason to the ones during the season who critics say, 'Why always Lukaku? Why always Lukaku? Why always Lukaku?'
"You have the answer - why always Lukaku, why always this, you have the answer. Probably we are not as good individually as people think and I keep saying if we finish second it's more than great, but now we need four points and we must try to get them."
United still need four points to confirm second place in the Premier League, with Mourinho indicating his players do not see finishing as runners-up to Manchester City as a key goal.
"Overall, attitude during the first half they were obviously stronger than us with more appetite, they felt it with different emotions," Mourinho said of Brighton's energetic performance.
"I didn't succeed in teaching my players the four points we need for second is important. For me it is."
