Manchester United manager Jose Mourinho says Marcus Rashford was on set-piece duty in the 2-0 win against Chelsea on Sunday because he is "trustable."
Rashford, 19, was a key figure in United's victory over the Premier League leaders, opening the scoring after just eight minutes at Old Trafford and causing problems for the opposition defence throughout.
The England international was also in charge of taking set pieces and it was his free kick that eventually led to Ander Herrera's second-half strike.
"Marcus is trustable," Mourinho told MUTV on why he selected Rashford to take set pieces.
"Even for the second goal, his free kick was really high, impossible to score from a header because it was to what we call the third post -- not the first or second post. But he's always tense, he's always fast, and you can always trust that [he will make] strong contact with the ball.
"The ball always goes with speed with him. With some other guys, the ball goes in the right spot but slower. Even if you win the duel in the air, it can be really difficult to score, so in this moment Marcus is one of the boys we trust.
"Because he's so young, he's able to keep developing that day after day; he's always with one of the assistant coaches trying to make it even better."
Mourinho challenged Anthony Martial on Wednesday to follow the example of Rashford if he wants to be a success at United.
While Mourinho was impressed with what he saw from his side against Chelsea, he is refusing to get complacent ahead of United's Europa League quarterfinal second leg against Anderlecht, which is finely balanced after last week's 1-1 draw.
"I don't allow them [to get carried away]," he said. "I want these people to be calm, you know; I don't like people to be in hell when the moment is bad and I don't want people to be in paradise when the moment is good. There is no time for that. We played amazingly well, it was a great result and a good feeling for everyone, but now we play a crucial match.
"Maybe the final of the League Cup was bigger, because it was a day to bring a trophy, but this one now is to go to the semifinals and either keep the dream alive or to finish.
"The result in the first leg was not phenomenal but it was positive -- we are in a positive situation. When the referee starts the game, we are qualified in that moment, and we obviously have 90 minutes to keep that position."
United can secure qualification for next season's Champions League by going all the way in the Europa League.
Mourinho, who criticised the Europa League after Rafa Benitez won it for Chelsea in 2013, says he would prefer to see his side in the Champions League, which is why they must do all they can to win Europe's second-tier club trophy.
"You know, my history and United's history -- which is much more important than mine -- is to be in the Champions League all the time," he said. "That's why United have never won the Europa League, and why I won it in the only year I played in the competition, back in 2002-03.
"We want to be in the Champions League, but since the beginning of the season, I keep saying, 'we are not.' We are in the Europa League -- that's the competition we can win. We've played 11 matches already, so let's see if we can go to the final."