Everton striker Wayne Rooney has said that he doubts that Premier League leaders Manchester City can go unbeaten in the league this season.

City extended their lead at the summit to 14 points with a 4-1 win over Tottenham Hotspur on Saturday, a result which means that the club have earned 49 points out of a possible 51 this term.

Former Manchester United man Rooney has said that City lack the staying power needed to go a full season unbeaten.

"I'm not sure [City] are quite there. They would have to keep going and do a lot more," he told talkSPORT. "There have been so many great teams throughout the years in the Premier League. This City team needs to win trophies and needs to do it for a longer period to be in that bracket.

"I don't think they can go unbeaten. "They have done incredibly well with the run they have been on, but the Premier League is so difficult, especially now with this Christmas period coming up.

I know they have a huge squad, a great squad of players. But there are so many top teams. I think in previous years it has been two teams and you went in knowing you would win most of the other games."

City's win over Spurs extended their top-flight winning run to 16 games.