CHELSEA kept the heat on Manchester United with a comfortable demolition job on struggling Sheffield United at Stamford Bridge.

The easy win came courtesy of goals from Andriy Shevchenko, Salomon Kalou and substitute Michael Ballack. United were also hit by the loss of Rob Hulse who was taken to hospital with a suspected broken leg.

It was Chelsea's sixth successive win in the Premiership since their defeat against Liverpool in January and their sixth clean sheet. The success also keeps them six points behind the leaders.

The result was never in doubt after Andriy Shevchenko put Chelsea in front after just three minutes. The goal owed much to the power and vision of Ricardo Carvalho who won the ball in his own half and burst through the middle before delivering a pin-point pass to the Ukraine striker on the edge of the area.

Shevchenko brought down Carvalho's pass with his right thigh and then despatched a glorious left-foot volley into the roof of the net.

The champions then increased their advantage in the 16th minute when Shevchenko helped a Shaun Wright-Phillips cross on for Kalou to score his second goal in three games with a simple tap-in.

United striker Rob Hulse tried to get the Blades back in the game minutes later when he produced an ambitious overhead kick from a Keith Gillespie cross, but his effort trickled wide.

However, it was Hulse's last contribution as he was carried off with a suspected broken leg after attempting to get on the end of another cross from Gillespie.

But despite the loss of their main striker, the visitors were still cuasing concern, and felt harshly treated moments later when they had a Claude Davis goal chalked off for handball inside the six-yard box.

Chelsea finally made the game secure however only minutes into the second half when Ballack - on for Frank Lampard - rose highest to meet a Wright-Phillips freekick and glance a header into the net from six yards.

Just when United must have thought their afternoon could not get any worse, Mourinho elected to send on top scorer Didier Drogba in place of Shevchenko in the 65th minute. The Ukrainian was given a standing ovation as he left the field for his outstanding display.

It was the perfect ending for Mourinho who would have been pleased by the way his players conserved their energies for tomorrow's all-important FA Cup replay with Tottenham.