When Andy Murray announced on New Year's Eve that he had hired Ivan Lendl as his new coach, various hypotheses were offered as to what the former world No1 could bring to the Scot's quest for a Grand Slam title.
Would it be the experience of losing his first four Slam finals before going on to win eight? The ferocious work ethic that took him to the top? Or maybe technical know-how that could transform the world No 4 into the world No 1?
Three and a half months in and all of the above may well be true - certainly the progress has been encouraging - but it is Lendl's lighter side, or perhaps that should be his dark side, that Murray revealed was coming to the fore.
"All he wants to do is hit people he's practising with," a relaxed Murray said. He opens his Monte Carlo Masters campaign against Serbia's Viktor Troicki on Tuesday.
"He's been trying to get me to do it. He says: 'As soon as this guy comes to the net just try and hit him.' That's his sense of humour. If he gets hit with the ball his reaction is to laugh. That's what gets him going, I guess, weird things like that."
Murray's methods are a little different. "You want to make guys feel intimidated by something you do on the court."
Technically, Murray's forehand has improved and he is trying to stand closer to the baseline during rallies. But it is interesting that Lendl the person appears to be as important as the advice he brings.
"When I look to the box and see him there I feel much calmer," Murray said. "At the Australian Open (where he lost in the semi-finals to Novak Djokovic), I felt pretty relaxed for most of the tournament."
Recovering from that defeat was the first true test for Lendl and he sailed through it.
"After I lost at the Australian Open, we sat down straight after the match and he got all the team around me," the Scot said, "whereas before, I'd kind of been left on my own, gutted. It wasn't like an: 'Oh, what happened there?' It was actually: 'How are we going to win the French Open?' and that was how we went about it."