Under Antonio Conte's stewardship, the Diego Costa of old has been terrorising Premier League defences on a weekly basis since the start of the season.
The Spanish international currently tops the division's scoring charts with seven goals already this term and looks to have completely recovered from an uncharacteristically disappointing campaign in front of goal during 2015/16.
Nevertheless, there was one very strange moment during Saturday's win over Leicester involving Costa that has landed him in hot water with his manager.
Mid-way through the second half, the striker was spotted gesturing towards the bench that he should be substituted.
With no sign of an injury, it was initially believed Costa was demanding to be taken off as he knew he was just one booking away from a suspension and the three points were already seemingly wrapped up.
However, it has now been revealed Chelsea's No.9 was actually fed up of the constant nagging he was receiving from the bench - and Conte in particular - so wanted to come off, according to the Daily Mail.
The Italian boss ignored the request and kept the forward on for the full 90 minutes.
And now it is also being reported that Costa has been warned about reacting that way during a match, with the same article from the Mail claiming he has 'been told to show more respect and curtail his angry gestures'.
You can certainly understand how Conte's hands-on approach could rub a volatile character such as Costa up the wrong way.
The former Juventus coach very rarely gives his players a moment's rest and really does kick every ball from the touchline.
It's very likely that Chelsea's Italian boss kept the striker on the pitch to simply make a point and remind him who the manager actually was.
It was still a potentially risky move, though, as if Costa did receive a booking in the final half-hour he would have missed Sunday's crunch clash with Jose Mourinho's Manchester United.
However, it has definitely put Conte's relationship with Costa under the immediate spotlight. Dropping the league's top scorer for persistent petulant behaviour would be an interesting call the Blues' manager may have to consider should his star man react like that again.