London - Antonio Conte revealed he ignored Diego Costa's request to be substituted because the volatile Chelsea striker's passion is too important to lose.
Costa scored his seventh Premier League goal of the season as Chelsea cruised to a 3-0 win over spluttering champions Leicester at Stamford Bridge on Saturday.
But the controversial Spain star still managed to cause a fuss with his demonstrative, but unsuccessful, attempt to convince Chelsea manager Conte to substitute him in the 70th minute.
Costa was one booking away from being suspended for next Sunday's home clash with Jose Mourinho's Manchester United and, with the game against Leicester well in control, he gestured that he wanted to come off.
He even clutched at his legs as if struggling with an injury in the closing stages, but Conte was unmoved and insisted he didn't want to lose a player with Costa's tone-setting aggression even for a few minutes.
"If I can, I keep Costa until the end of the game. Costa is an important player for us," Conte said.
"Diego is in good shape. He has passion and we need his passion in every moment of the game.
"I know I risked it because if Costa took another yellow card he misses the next game.
"I decide the substitutions. Always I take the responsiblity in every situation, good or bad."
Conte was also rewarded for sticking to his beliefs about playing three central defenders.
Having changed to his preferred formation after Chelsea leaked too many goals, Conte was rewarded with a second consecutive clean-sheet despite leaving fit-again captain John Terry on the bench.
"I changed the system because it's important to have time to understand the right characteristic for the team," he said.
"After we conceded a lot of goals I decided to change for the Hull game. This system suits the talents of all our players."
Conte had laughed off suggestions he was about to be sacked after some bookmakers suspended betting on his departure on Thursday.
And Chelsea's best performance of the season was a welcome vote of confidence.
"I'm quite 'tranquilo'. I'm very happy," Conte said. "When you work so hard during the week, it's logical you want to see a good result.
"I'm very happy, above all for my players."
Meanwhile, Claudio Ranieri admits Leicester's maiden Champions League voyage is ruining their Premier League title defence.
Ranieri's side are 11 points behind leaders Manchester City after their fourth loss of the season.
That is more defeats than Leicester suffered in the whole of last season and they are also the first English champions to lose four successive away games since Blackburn in 1995-96.
Ranieri believes he and his players have become too focused on their European adventure.
"When you play in the Champions League for the first time in the club's life, the concentration can be very high in the Champions League and it is not the same in the Premier League," Ranieri said.
"I can understand this. It is not only one man who changed the team, it is the brain that changed the team.
"I'm not worried. I know my job. There are good and bad moments. I have to work."
Ranieri conceded he might have unsettled his team by resting three key figures, including last season's player of the year Riyad Mahrez, to keep them fit for Tuesday's Champions League clash with Danish side Copenhagen.
But the Italian was unrepentant because he believes reaching the knockout stages would be a huge achievement for a club of Leicester's stature.
"The Premier League is one year long, the Champions League is two months and you are in or out," he said.
"We want to go in the knockout in the Champions League, to achieve this you have to have all your players fit. I prefer to keep players fit for Tuesday."