Manager Louis van Gaal believes Manchester United's chances of finishing in the Premier League top four remain in their own hands after they returned to winning ways against Crystal Palace.

United recorded a victory for the first time in four attempts, but they made hard work of their 1-0 triumph against a spirited but limited Crystal Palace at Old Trafford on Saturday.

"I am happy with the three points and we stay in the race to end in the places that we want to be in," Van Gaal said. "We stay two points behind fourth place. It's in our hands and that's important."

Juan Mata scored the decisive goal in the 67th minute, four minutes after being introduced as a substitute.

The Spanish midfielder's shot from 22 yards was fierce and a slight deflection meant Palace goalkeeper Julian Speroni could not keep it out.

It was Mata's third goal in a campaign of limited opportunities, and the former Chelsea playmaker came close to adding to his tally when he hit the post with three minutes left.

With Marcus Rojo, Rafael, Phil Jones and Jonny Evans all injured and Chris Smalling suspended, Van Gaal was again forced to field an unfamiliar defence.

Paddy McNair and Daley Blind were chosen as central defensive partners and they helped United keep a first clean sheet since the 4-0 win over Queens Park Rangers on September 14.

Van Gaal said the improvement was not only due to the defence.

"It's not a matter of defence, it's a matter of organisation when we don't have the ball," said the Dutchman. "It means that it's the whole team who have to defend. Today (Saturday), we were better in that shape.

"In spite of that, before half-time there was a misunderstanding between McNair and Blind and it could be 0-1 and maybe I sit here differently. That's football also.

"We had patience, but we need more speed and more switches. We had a lot of time on the ball, created big chances and possibilities. We could have scored in the first half.

"I think we played better in the matches before because we kept patient. After Mata scored, I think we created more big chances because then they have to come forward.

"We have to finish these chances because they were big chances. I was pleased because the team was deciding to kill the game and I say that several times -- when we are ahead, then you have to kill the game."

Palace are now without a win in five matches. They came to Old Trafford with an apparent plan to frustrate their hosts by defending in numbers and relying on counter-attacks to pose a threat, and it almost worked.

Indeed, the London club could have taken the lead five minutes before half-time when hesitation between McNair and Daley allowed Joel Ward's long ball from the back to reach Fraizer Campbell.

The former United striker lifted the ball over David de Gea but, fortunately for United, it also cleared the crossbar.

"I think that's the best opportunity I've had to beat Man United," said Neil Warnock, the Crystal Palace manager.

"The chance we missed was the best opportunity of the game with Fraizer Campbell. If we could have got in front then the crowd would have grown restless.

"It would put a lot more pressure on their side then, because they're expected to beat Crystal Palace."