As one half of the Williams sisters, Venus has had had more practice than most at maintaining a competitive, almost dispassionate approach when playing tennis against someone you care about off the court. And you suspect that her matches against her sister Serena have helped Williams to find the right mindset for her potentially awkward encounters with Caroline Wozniacki, a friend and former doubles partner.
Certainly, Williams has been relentless in her past matches against Wozniacki, winning all seven of them. There has been no let-up from Williams; she's hardly going to take some pace off her serve, or her forehand, just because she's friendly with Wozniacki, and it also doesn't appear as though she has been unconsciously kind towards the Dane in their matches either. With just one win from her 11 matches against Serena, Wozniacki's combined record against the Williams sisters is 1-17, though she will have the opportunity against Venus, in Sunday's WTA Finals showdown, to reset the way their matches go.
Still, it's not as if Williams, who turned 37 this year, is showing any signs of fading away, playing in two Grand Slam finals this season. Only once in their series, when they met in the 2015 Auckland final, has Williams even given up a set against Wozniacki, who is 10 years her junior.
That's not to say that meetings between these two former world No. 1s are lop-sided as when they last played, in the quarter-finals of the 2015 Miami tournament, the second set went to a tiebreak. And this series has been low on carbs, with no bagel 6-0 or breadstick 6-1 sets.
Before she started competing on the WTA Tour, Wozniacki would often watch Williams playing on television, and wonder about the power of the American's serve. Their first match came on a hard court in Memphis in 2007. And every one of their meetings have been on the same surface - in Japan and Thailand that same year, and then in Miami in 2008, while there was then a six-year break before they met again in Dubai in 2014. In 2015, they played twice, in Auckland and Miami.
As Wozniacki once observed: "Venus is a great, great player. Going out to play her, you know that it's not going to be easy."