Chelsea bounced back to winning ways after successive Premier League defeats as they beat Hull City 2-0 at the KCOM Stadium.
The hosts enjoyed the better of a cagey first half but went behind when Willian swept home a curling shot after good work from Diego Costa after the break.
Costa found the top corner with a similar strike to double the lead after Nemanja Matic's powerful run.
Hull never recovered and could have been further behind but for Pedro's poor finishing from six yards.
Chelsea manager Antonio Conte promised "a solution" after his side went down with a whimper against Arsenal last weekend and he found his answer in a strategy he used at former club Juventus.
The Italian opted for a three-man defence during much of this trophy-filled time in Turin and deployed Gary Cahill, David Luiz and Cesar Azpilicueta at the back as he organised his Chelsea rearguard to match.
It did not initially appear to have stabilised a side who had conceded nine goals in their last four games in all competitions.
Luiz lost track of Dieumerci Mbokani as he apparently struggled with the extra space he and his team-mates had to cover and was fortunate that the Hull striker's control betrayed him.
But the defence, along with the team as a whole, improved markedly after half-time and never looked like blemishing only their second clean sheet of the season.