Chelsea manager Antonio Conte hailed Diego Costa as "a warrior", while John Terry's influence in the dressing room also attracted praise from the Italian.
Costa sits joint top of the Premier League goalscoring charts with 11 - level with Arsenal's Alexis Sanchez - and looks to have regained the form he showed in his first season in England, when his 20 goals fired Chelsea to the title in 2014-15.
The Spain international has managed to curb the aggressive streak to his game that threatened to undermine his performances in the past, even staying out of trouble as tempers flared between Chelsea and Manchester City players last week.
"It's very good because Diego is showing the right part of him now," Conte said prior to Chelsea's fixture with West Brom at Stamford Bridge on Sunday.
"Before, it wasn't right always to say Costa showed 'bad passion'. But now he's showing the right part of his character.
"Diego is a real warrior. He's good for the team, because it's important to have many warriors during the game. Every game is a battle - a sporting battle - and it's important to have warriors in your side.
"Diego is showing his great passion, and showing that he can put his passion in the team in the best way. It's fantastic for him and for us, the team, the club and the fans. He's playing very well and we're working a lot to involve him in our play. He's improving a lot, Diego."
Conte also hailed Terry's professionalism, the club captain currently out injured with a muscular problem in his buttock.
"He's still a footballer who is just injured at the moment, but he's continuing to be a leader in the changing room," Conte said.
"John asked me if he could come with us to Manchester City and stay with us before and during the game. That was important for me: John is our captain and you are a captain if you play or not, or if you are injured or not.
"He's showing great commitment at the moment, and I'm pleased with this."