Liverpool boss Jurgen Klopp said Diego Costa was "not the nicest guy," and he "could never be friends" with him after the Chelsea forward won a controversial penalty during a 1-1 draw at Anfield on Tuesday.
Reds defender Joel Matip was adjudged to have fouled Costa in the area to hand the visitors the chance of all three points. However, Costa's resulting spot-kick was saved low to his right by goalkeeper Simon Mignolet.
After the match, Klopp spoke of his frustration over the penalty award. Per the Press Association (h/t ESPN FC), he said:
If I had played against Costa I could never be friends, that's how it is, but when you have him in your team it's much more fun. He is a warrior. What [Antonio] Conte is doing with Chelsea is outstanding but Chelsea without Costa this season....?
... He is not the nicest guy on the pitch but I saw no real big incident and until someone tells me something...
If someone tells me it was a dive maybe I will be angry tomorrow but that would be the wrong decision what, number 27, but it doesn't make it better.
Georginio Wijnaldum's second-half strike cancelled out David Luiz's opener for Chelsea to earn a point for Liverpool, which stemmed their recent run of poor home form.
Opta highlighted Mignolet's penalty record:
Klopp is not the first manager to question Costa for his approach to the game. Arsenal boss Arsene Wenger was suggested in 2015 the player "is always provoking," per Clare Lovell of Reuters.
However, compared to the last campaign, this season has seen the Spain international talked about more for his goals than his antagonism of opposition defenders.
Costa is the joint leading goalscorer in the Premier League this season, sitting on 15 goals alongside Arsenal's Alexis Sanchez. Indeed, his current form is reminiscent of when he first arrived in England in the 2014-15 season when his goals led Chelsea to the title.
The turnaround in Costa's approach is certainly benefitting Antonio Conte's bid to win the title in his first season at the club and the result at Anfield edged them that bit closer. Chelsea are now nine points clear of second-placed Tottenham Hotspur.
The striker is arguably the Chelsea talisman, and a much calmer one this season.
As Steve Stammers of the Daily Mirror noted in an appraisal of Conte's management skills: "Somehow Conte has got into the mind of Costa."
While Costa hasn't appeared to court the bad headlines as much, he has lost none of his robust, aggressive playing style.
He is a player who relishes the physical side of the game in England and as such has been able to adapt perfectly to Premier League life since his arrival from Atletico Madrid in July 2014.
Costa's strength and ability to lead the line and bring midfielders Eden Hazard and Pedro into the game are crucial to the Blues' attacking thrust and the 28-year-old's importance to the club cannot be over-estimated.
He was heavily linked with a move to China in the January transfer window, per Calciomercato, an issue which looked as though it might derail Conte's bid for success this season.
And while it is debatable whether Costa will remain at Stamford Bridge past this season, for now Conte's firm-handed approach is paying off for Chelsea.