Liverpool's victory over Manchester United had opened the possibility of an exciting climax to the Premier League season, says Chelsea manager Guus Hiddink. Chelsea ensured they kept up the pressure on leaders United thanks to Michael Essien's first-half winner against Manchester City at Stamford Bridge yesterday.

It put the Blues back into second place, ahead of Liverpool on goal difference, and just four points behind United.

But Hiddink is still extremely wary of United's game in hand on the rest of the chasing pack.

"If it was just four points it would be very close, but they have that game in hand," said the Dutchman. "But it's clear that after Saturday'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 to 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, then all of a sudden it happens.

"But they're a very experienced team. 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.

"I don't know what their reaction will be. When you are in the driver's seat and someone else is coming, you can get a little bit nervous. It is a little bit open now."

Hiddink, who has agreed to remain as Chelsea coach until the summer, likened himself to a "schoolboy" when it comes to the task of chasing experienced campaigners like Rafael Benitez and Alex Ferguson.

But he insisted the title would be decided by the players and not the managerial personalities.

"It's not a battle between the managers," added Hiddink. "It's a battle between the players.

"They're both very experienced - Rafael is experienced and Sir Alex is very experienced. Let me, as a schoolboy, chase them. At the end, it's the players."

If Hiddink’s side are to keep up the pressure, it will have to be done without playmaker Deco, after the Portugal international aggravated a hamstring problem in the win over City.

Deco has been troubled by the injury for the last two months and was substituted in the first-half. Now Hiddink says it is very doubtful that Deco will return before the end of the season.

"He was fit and worked hard, but after 20 or 25 minutes he had this problem again, so he will be out again for a while," said Hiddink. "I think Deco will not be recovered very shortly. He'll have to be very fit to come back this season. I have my doubts to be honest, but let's see what happens."