Manchester United registered a 1-0 narrow win over Manchester City during the derby clash at the Etihad on Sunday. The Red Devils manager Louis van Gaal has confirmed star duo of Marcus Rashford and Matteo Darmian came down with cramps, which was the reason for their struggle on the pitch.

The Italian international was the third and final substitution for United as he was replaced by Timothy Fosu-Mensah. The full-back was complaining about the cramp, which led to his withdrawal from the pitch.

After that, even Rashford was also struggling on the field. Despite that, the young striker played the entire match as the Old Trafford club had completed all their substitutions.

United’s victory over City comes just three days after they were eliminated from the Europa League by their arch-rivals Liverpool. The former Barcelona manager has suggested the number of fixtures has taken a toll on several players and played down any injury concerns for Rashford and Darmian.

“The second half we had chances to score the second, but then we fought until the end and survived,” Van Gaal told United’s official website.

“A lot of players had cramp, but that’s logical I think when you play on Thursday too. I think it [the performance] was fantastic. We did it also against Arsenal after playing on a Thursday and beat them and we have beaten Manchester City also. I am very happy because it’s not easy to win here.”

Rashford scored the only goal of the match for United against Manuel Pellegrini’s side. That is the striker’s fifth goal in all competitions and third in the league. He was the star player for the Red Devils during their 3-2 victory over Arsenal and has now excelled against City.

Van Gaal was in full praise of the teenager, but has underlined that United should be patient regarding his development at the club.

“He is a real striker and that’s why I played him in that position because he can make goals and he is also an attacking point and runs the channels. I like him very much, but still he is 18 or 19 years old so we have to wait and see how consistent he is,” he said.