To the surprise of no one, it turns out that John McEnroe is a more excitable courtside presence than Ivan Lendl.
On the occasion of the Queen's Club final, Lendl surpassed himself. Having been as static as a net post during more than two hours of exhilarating tennis, he didn't hang around afterwards, leaving an empty blue plastic seat during Andy Murray's trophy presentation. It was as if someone had unplugged the Lendl hologram.
Contrast with McEnroe who, if he wasn't fidgeting during and between points, was jumping out of his chair to support Milos Raonic or clapping his hands or calling out. Lendl would not dream of doing anything like that.
Here at Queen's was a preview of how Wimbledon might look this summer. When people talk about a difference in styles at the All England Club, it won't just be strategies on the grass, but the approaches in the players' guest boxes. The resumption of the Lendl-McEnroe rivalry is certainly an intriguing one.
They aren't the only grass court retro acts. This summer sees a second wave of supercoaches in men's tennis.
It was Murray's first alliance with Lendl, twice a runner-up at the All England Club, which made it fashionable for players to turn to legends of the game.
And now Lendl and Murray have reformed their partnership as the Briton seeks his first Grand Slam title since winning Wimbledon in 2013.
Meanwhile, McEnroe, three times a Wimbledon singles champion, has taken up his first coaching role since working with Boris Becker, a relationship which faltered for the simple reason that, in the New Yorker's analysis, "Boris didn't listen to a single word I said".
And, 20 years after winning Wimbledon, Richard Krajicek is back on the grass court scene, this time as a coaching consultant to Stan Wawrinka.
Is anyone watching these developments more closely than Becker, who has had such great success with defending Wimbledon champion Novak Djokovic?
Becker was a little taken aback by news that Murray would be returning to Lendl, just a week after Jamie Delgado had coached the world No.2 to a first French Open final.
"I think it's great for the game that stars like John and Ivan are back in it, and it's good for the quality of the tennis," Becker said in an interview with the BBC.
"Let's face it, we do understand the game probably better than most, so everyone benefits."
Naturally, Lendl and McEnroe's coaching rivalry isn't going to have the same intensity as those wild days in the 1980s - that era of very short shorts and even shorter tempers - and it certainly won't be as vicious.
Think of the time when McEnroe suggested that he had more talent in his "little pinkie" than Lendl had in his entire body, or when he accused his rival of "strange sulks and weird head trips".
Or the occasion when Lendl drilled the ball at McEnroe and then turned away from his battered, floored opponent to hide his laughter.
Their rivalry generated so much heat, noise and Cold War-era soap opera, as well as three Grand Slam finals. One disappointment was that their 36-match mini-series only saw one Wimbledon meeting, which came in the semi-finals of the 1983 Championships and won by McEnroe in straight sets.
On a visit to Queen's Club last week, where he was honoured in an on-court ceremony, the three-time Wimbledon champion spoke backstage to McEnroe and Lendl about why they had been compelled to return to the competitive arena. "What was that first practice like? How does it feel to be sitting by the side of the court?" Becker asked McEnroe.
With Goran Ivanisevic still employed by Marin Cilic, there will be no shortage of former Wimbledon champions working as coaches at the tournament even if Stefan Edberg, in Roger Federer's corner for the past two summers, has departed the scene. Ivan Ljubicic is now the voice in Federer's ear.
Now in their fifties, they are considerably more restrained, but underneath all that civility, those competitive fires still flicker and flare. Murray's Queen's Club victory would have been all the sweeter for Lendl because it came through beating McEnroe's player. There's only way to top that - for Lendl to achieve a coaching victory over McEnroe in a Wimbledon final. He might even stay in his seat after that one.