Wayne Rooney insists Manchester United can overtake Chelsea and win the Barclays Premier League this season.

United stretched their winning streak to six matches on Sunday with a morale-boosting 3-0 victory over arch-rivals Liverpool.

Despite struggling in the opening stages of the season, Louis van Gaal has guided his men to third in the table and they are now eight points shy of leaders Chelsea, who are three points ahead of second-place Manchester City.

So far this season Chelsea have looked superior to United, but that does not faze Rooney.

The striker was part of the team that won the league six seasons ago despite trailing Liverpool by eight points in January and he also remembers United's last triumph in 2013, when they won the title by 11 points despite rarely blowing sides away.

"I think we have to believe we can win the title," Rooney said.

"We are eight points behind and coming into a busy period.

"If we can win our games and the others have one bad result then there is nothing there.

"We have to keep winning our games and hopefully get back to the top and you never know.

"We won the league two years ago and we weren't great in a lot of those games but we got the results.

"We have shown a great resilience this season. Some of the games haven't gone the way we would like but we are winning them and that is a great quality to have.

"We have been here before but we have a lot of new players and this is where the experience of myself, Michael Carrick and Darren Fletcher can rub off on the other players."

Rooney points to several factors behind United's resurgence.

The superb form of David de Gea was the most pertinent one in his mind following the United goalkeeper's latest top-class display.

While Liverpool helped United with an abject defensive performance, De Gea played a big part in the 3-0 win too by pulling off superb saves to deny Raheem Sterling and Mario Balotelli.

"In my eyes he is the best keeper in the world," Rooney said without hesitation.

"Sometimes in training you hit a shot and turn away thinking it has gone in and he just manages to get there.

"He came through a tough patch early on in his career here and he is starting to prove what a top keeper he is.

"I hope he wins some of the top personal awards. He has had a really good season."

Rooney also feels the players have started to understand Van Gaal's demands in training and on match day.

"We are all aware of what the manager wants now both on and off the pitch," Rooney added.

"We all bought into his ways. He is a great manager. He is great with the players.

"He is honest with the players who are players and those who aren't which is great.

"We have a great team spirit. Everybody is pulling together. We all want to win. We all want to be successful. As long as we keep working we won't be far away."

Rooney's flexibility is one of the reasons why the striker's love for his manager is not unrequited.

Despite missing part of the season through suspension and injury, Rooney has found the net six times.

Many of those goals have come from the striker's position, but he has also looked effective in the number 10 position just behind.

And on Sunday Rooney played as a central midfielder.

In the summer the United skipper said he was reluctant to play in midfield at this stage of his career, but he was happy to operate there on Sunday.

And Rooney believes the move could be beneficial long-term.

"I think it can help me in years to come," he said.

"You see top players retire like Michael Owen, for instance.

"He was one of the world's best players but I don't think he could drop back into midfield so once his pace had gone through injuries that was kind of the end.

"But I feel I can drop back and I am sure it will give me an extra few years at the end of my career and it will also help me if I go into management."