David Moyes believes that David de Gea's performances in goal have made him as valuable to Manchester United as Wayne Rooney or Robin van Persie. De Gea made a late save to deny James Chester an equaliser in United's 3-2 Premier League victory at Hull City on Boxing Day and Moyes says moments such as those are as significant as the contribution made by his strikers at the other end of the pitch.

Life in England has not always been easy for De Gea since he arrived from Atlético Madrid two years ago and there have been times when the 23-year-old has struggled to come to terms with the physicality of the Premier League. Yet De Gea has grown in stature, becoming increasingly dominant in his area when United are defending crosses and set pieces.

"Wayne and Robin score big goals and win games for us, but David has won us big points as well," Moyes said. "His save at Sunderland comes to mind and he did it again in this game, he made some good saves for us. He is also coming and taking crosses and being brave and we want him to do that.

"I look round and he is one of five or six young players in the team who are going to be part of the next five or six years, and that means he can only get better. He was always going to get better."

Moyes feels that the faith shown in De Gea by Sir Alex Ferguson, who signed him for £17m when he was 20, has helped the Spaniard improve. Ferguson occasionally protected De Gea by playing the more experienced Anders Lindegaard instead, but always stuck by him when the critics were circling.

"One of the hardest things to do is put a young goalkeeper in; he made a few mistakes, but Sir Alex stuck with him," Moyes said. "He really trusted him and believed in him, and we are seeing the fruits of that. He is now turning into a man and getting stronger, and looking at the top of his game.

"He is getting used to the Premier League and understanding what he has to do, he is coming and catching and taking things, sometimes that is what you have to do, you have to be brave. He is punching well too. He has done good work with [United's former goalkeeping coach] Eric Steele and now with Chris Woods. The defenders have always trusted him because they knew the potential for him to get better was there."

United, who visit Norwich City on Saturday, recovered from going 2-0 down after 13 minutes to defeat Hull, something Chris Smalling believes offers proof that they should not be written off as title contenders, even though they are eight points behind the leaders, Arsenal. "We did that quite a few times last season and we've done it again here," the defender said. "It shows a real togetherness about us. We've got a bit more belief showing right through this whole team."

Having suffered successive home defeats by Everton and Newcastle at the start of December, the champions have won their past five matches in all competitions and are quietly making up ground on their rivals.

"We hope they are getting nervous," Smalling said. "We are starting to get on a good run and if people are starting to look over their shoulders, then we are doing a good job. It's one of those seasons where there are going to be a few ups and downs, and some teams have yet to have their downs. We have had our blip."