Manchester United striker Javier Hernandez says they cannot afford to slip up at Chelsea.

United have not won in the League at Stamford Bridge since 2002.

"Every little slip will have an effect on the title race at the moment so this match against Chelsea is very important," Hernandez said. "Winning in London is vital. Chelsea are always dangerous and they will raise their game.

"Also the Blues need the points themselves to climb the table.

"I can't say whether this is a crisis game for Chelsea or not, but they certainly have not been playing as well this season as they have been in the past.

"Losing against Liverpool in the FA Cup was not ideal and the game did not go to plan.

"The one thing now is that we can focus totally on the league and that is what we want to win. The manager is very serious about us winning the title and considers it to be a mental question because every week is a big race, and he knows that this club have shown the right character in the past to win."