Chelsea claimed a hard-fought 2-1 win at Stoke on Saturday that maintained their 10-point lead at the top of the table going into the international break.
Willian and Gary Cahill scored either side of Jon Walters' equaliser, though it was Costa who once again took centre stage at the bet365 Stadium.
Referee Anthony Taylor cautioned Costa on 16 minutes for dissent when the Spain international was not awarded a free-kick for a blatant dive.
The Spain international showed more restraint in the remaining 74 minutes to avoid further punishment, despite being clattered into by both Phil Bardsley and Bruno Martins Indi.
The 28-year-old had almost as many bookings - 10 - as goals - 16 - last term, but he has found the net 18 times this term with seven bookings to his name so far.
And goalkeeper Courtois thinks that while it is unlikely Costa will win any fair play awards this season, Chelsea's leading goalscorer now knows how to better control his emotions.
"They were very physical and it was hard to find our usual game," the Belgian said of Stoke.
"They tried to put our players out of the game by doing that. They know Diego doesn't like it and he maybe starts to fight with people.
"Maybe they do this to get him a red card or something.
"In some moments maybe Diego exaggerates a bit as well, but I think most of the time they were hitting him quite well.
Antonio Conte's crazy celebration after Gary Cahill's winner against Stoke
Sat, March 18, 2017Antonio Conte went a little bit mad after Gary Cahill's winner against Stoke City at the bet365 Stadium, and the home side won't be too pleased with the Chelsea manager
Chelsea manager Antonio Conte got pretty excited about Gary Cahill's late winner
"After four or five 50-50 moments where the referee can whistle or not whistle, he gets a bit angry and gets a yellow card.
"So it's important for him to stay calm and he's developed that a lot this season.
"When they kicked him, he remained calm and that's very good for us because in the worst case, he would have got a second yellow card and been out of the game.
"It's a good job he remained calm and dealt with what happened to him and moved on.
"Diego is the type of guy who has a lot of energy and goes for every ball and he gets kicked as well.
"People know how he is as well and a lot of Stoke players got a yellow card for fouls on him. He was always calm and he does well for us."