London:Guus Hiddink insisted the Premier League title race is far from over after Chelsea narrowed the gap on leaders Manchester United to just four points.
Hiddink's side responded to United's shock 4-1 home defeat to Liverpool by beating Manchester City courtesy of Michael Essien's first half goal.
While the Chelsea manager acknowledged that the advantage still lies with Sir Alex Ferguson's side, who have played a game less, he claimed the weekend's results could have a major impact on the eventual destiny of this year's championship.
Hiddink believes the decisive factor will be how United react to the shock of being humbled at Old Trafford by one of their fiercest rivals.
Hiddink said: "If it was just four points it would be very close, but they have that game in hand. But it's clear that after Sunday's unexpected result that the tension has come back in the league.
"It's a boost. But if we want to track them, we have to keep on winning. That'll give tension at the end of the season, which is good for everyone."
"Every now and then you get a defeat you don't expect. Sometimes you don't expect it at home because you have a beautiful record at home, then all of a sudden it happens. But they're a very experienced team," Hiddink said.
"Let's see how they react in the up-coming days. It's not the first time that it's happened, but the big teams always react.
"It depends on their calmness if it goes on. When you are in the driver's seat and someone else is coming, you can get a little bit nervous.
But a successful afternoon's work was marred by a recurrence of Deco's thigh injury that could keep the Portugese midfielder out for the season although Hiddink was more optimistic about the knee injury that forced Didier Drogba off in the second half.
"I don't think Deco will be recovered very shortly," added Hiddink. "Drogba is not a big problem. He likes to be with the team, to play, to train, so I think he will be recovered very soon. He was in a collision, so we'll see. Tomorrow, the day after, it'll be okay."