Watford 0 Chelsea 1: Last-gasp Kalou heads off the Chelsea concession

The home crowd's chants directed at Jose Mourinho predicted, "You're getting sacked in the summer". If so, this game illustrated why. Roman Abramovich, the man likely to administer the chop, sat glumly watching a thoroughly uninspiring performance that on the balance of chances created could even have brought an embarrassing defeat.

Then, in added time, Salomon Kalou, one of three substitutes brought on in the first hour by a dissatisfied Mourinho, headed an undeserved winning goal to peg Manchester United back to a six-point lead again. Until that moment Watford, rooted to the bottom of the table and surely doomed, were set to remember this as one of the more enjoyable days of their Premiership adventure.

What can be said for Mourinho is that he does all he can from the sidelines. Having started looking hands-in-pockets relaxed in the sunshine, he quickly grew restive at Chelsea's failure to seize control, changing the system at half-time with two substitutions, then changing it again within 15 minutes.

This would not be a man to stand by and hope for the best while an England team struggled against opposition such as Israel and Andorra.

"The only good things we had today were attitude, belief and the keeper [Petr Cech]," Mourinho said. "Maybe it's a little unfair on Watford but our belief deserved that little bit of luck. If you have to die, it's better to die giving everything." But he is not yet ready for a funeral, claiming: "I can see United dropping six points."

For an hour before they kicked off, Chelsea had hoped against hope that two or even three of those points might be surrendered to Blackburn at Old Trafford. By half past four, however, the pressure was back on and the response was poor.

It took more than half an hour to force Watford's goalkeeper Ben Foster - acclaimed by the home crowd as "England's No 1" despite being beaten by Paul Robinson at White Hart Lane two weeks ago - into a serious save. He did well to stop Didier Drogba's shot with a foot after the Ivorian swivelled smartly on to Frank Lampard's downward header.

By the time additional time was signalled, however, Foster's only other work involved a more orthodox save from Andriy Shevchenko. Then Michael Ballack made his one significant contribution of the afternoon, winning a tackle to help set up Shevchenko on the right. The cross was perfect for Kalou to nod in at the far post and keep the Premiership race alive - albeit on life-support. Missing Arjen Robben, injured playing for Holland in midweek to his manager's frustration, Chelsea took the narrow option, playing Shaun Wright-Phillips but initially using him and Lampard as the widest points of a diamond which was not very wide at all. The full-backs were supposed to supply the genuine width, but Gérémi and Ashley Cole were disconcerted to discover how much defensive work was demanded of them as Watford pressed forward with uncomplicated vigour.

John Terry found an uncomfortable week continuing when he was laid out in the first minute. Soon afterwards, Steve Kabba's imaginative overhead kick was well saved by Cech. Douglas Rinaldi, a Brazilian on his full debut, raced past Chelsea's two central defenders before Ricardo Carvalho recovered to concede a corner and Darius Henderson struck a fierce volley just over the bar.

Paulo Ferreira and Kalou duly appeared for the second half and soon Jon Obi Mikel came on as Chelsea switched to a back-three. In between times Watford should have scored, Kabba shooting wide from six yards following a long throw. It took another fine save by Cech to deny Damien Francis from a late corner before the dramatic final act.