The Spain international scored Chelsea’s opener in a 3-0 win against reigning Premier League champions Leicester City at Stamford Bridge on Saturday afternoon.
Costa has now scored seven times in eight Premier League games this season under Conte following the Italian’s appointment as Chelsea manager ahead of the summer.
The former Atletico Madrid man netted 20 times in 26 Premier League games as the Blues won the top-flight crown in the striker’s first season in England in 2014-15.
However, Costa only managed to score 10 times in an awful campaign for the west London side under Jose Mourinho and Guus Hiddink last term.
Former Chelsea manager Vialli believes Costa is feeling the love under Conte and the manager’s support has helped to trigger the striker’s return to form.
“He is more focused and he knows what he has to do to win games and to score goals. Antonio Conte likes him very much as well,” Vialli told Sky Sports.
“I think he feels that the manager has confidence in his ability. When you play with a manager who loves you, your performances improve a lot.”
Chelsea will host Manchester United in their next Premier League game on Sunday 23 October when Mourinho returns to Stamford Bridge for the first time since his sacking back in December.
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