Angel Di Maria-Wayne Rooney
Angel Di Maria was replaced after the half time against Sunderland.[Getty]

Manchester United captain Wayne Rooney remains hopeful Angel Di Maria will regain his form as the club record-signing continued his poor display during Sunderland win.

The Argentine international arrived at Old Trafford for a British record transfer fee of £59.7m from Real Madrid last summer. He had a quick impact early in the season, but has struggled in the last few months.

Adnan Januzaj replaced the 27-year-old before the start of the second half after he failed to impress in Red Devils' last league win. Louis van Gaal admitted Di Maria needed time to adjust to the Premier League.

Rooney remains confident the South American will be a key player at United for the remainder of the season as the 20-times English champions look to finish the campaign in the top four.

"Of course he has. Today was one of those days that every footballer has. He is a great player, he has shown that and you don't lose your talent overnight. Hopefully he will get back to his best and start giving some great performances for us," Rooney explained.

"He has got a lot of experience and I think he will figure it out. We all have to do that sometimes."

"There is nothing worse than when everyone keeps going on at you. You have to come to it in your own way and I'm sure he will be a big player for us between now and the end of the season," the England international concluded.

Rooney scored twice for United during their 2-0 victory over Sunderland. The 29-year-old was playing as a striker against the Black Cats after playing the most part of the last few months as a midfielder.

United winger Ashley Young was full of praise for Rooney for his impressive display against Sunderland.

"There'd just been a man sent off and he was waiting around for the referee to blow his whistle – that's when you've got to keep your focus. He kept his cool, kept his focus and slotted it away – that's Wayne all over. It was a great performance from him today," Young told United's official website.

"We came out in the second half fully composed; everyone wanted to get on the ball. We got our chance, Wazza scored the penalty and we didn't look back."