Last updated on .From the section FA Cup

Chelsea were far from their best but progressed to the FA Cup fourth round at the expense of Championship Watford thanks to three second-half goals.

After a drab first half, Jose Mourinho brought on Willian and Diego Costa who provided some much-needed spark.

Willian struck from 25 yards to give the hosts the lead while Loic Remy doubled Chelsea's advantage with a well-taken half-volley from 12 yards.

Kurt Zouma completed the scoring, heading in Cesar Azpilicueta's cross.

With the influential quartet of Cesc Fabregas, Nemanja Matic, Costa and Eden Hazard not starting - Jose Mourinho made eight changes to the team which lost to Tottenham - it was perhaps no surprise the hosts did not immediately click.

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But Mourinho's men have suffered a dip in form of late, letting an eight-point advantage in the Premier League slip.

Chelsea lacked creativity and control in midfield, with Watford, fifth in the second tier, initially reducing the Premier League co-leaders to half-chances - a flick-on from a free-kick for Gary Cahill and then a glancing header from the defender.

It was no surprise to see Mourinho make changes at the break, but the Hornets' energetic pressing and physicality continued to stifle the Blues in the early stages of the second half.

Watford nearly took the lead when Troy Deeney's hopeful shot deflected off Filipe Luis, narrowly missing the bottom left corner.

But within minutes, Chelsea were ahead thanks to Willian's fabulous arrowed strike into the top-right corner.

Watford initially refused to cave in, but crumbled once they fell further behind courtesy of Remy's impressive half-volley, with the Frenchman pouncing while his team-mates appealed for a penalty for handball.

Kurt Zouma polished the script for the hosts, powerfully heading into the top corner to inflict a fifth loss in six FA Cup ties for Watford against Chelsea.