Stanislas Wawrinka and Tomas Berdych have spent a fair amount of time together in recent years. In 2013, they’ve played four times in singles, and this spring they stared across a net at each other for seven hours and one minute in a Davis Cup doubles match. These two 28-year-olds know each other's games well.

But Stan seems to have a much better understanding of Tomas. While Berdych is the higher-ranked and more accomplished player, Wawrinka, after his 6-3, 6-7 (0), 6-3 victory at the World Tour Finals in London today, has won six of their last seven matches dating back to 2010. This one made you understand why. From the outset, Wawrinka controlled the rallies, opened up the court, and played with confidence. He was the better player from start to finish, and only a bad patch at the end of the second set, and a surprisingly clutch tiebreaker from Berdych, kept it from ending in straights.

Wawrinka hit 43 winners and saved all five break points against him. Berdych, who was unusually passive, managed just five winners with his best shot, his forehand. In the first set, he double faulted at 2-3, 30-30, to hand Wawrinka the only break point he would need to win the set. In the third, Berdych’s first serve—he hit 14 aces for the match—was all that kept the score close. Once the rallies began, Wawrinka dominated.

The 6’5” Czech had more trouble moving and hitting through the traditionally low-bouncing hard court that the ATP lays down for its year-end championships than his opponent did. But this is a bad match-up in general for Berdych. He can dictate the action against Wawrinka’s countryman, Roger Federer, but he can’t do it against Stan himself. Today, Wawrinka was too strong from both sides to be backed up, and his kick second serve gave Berdych fits. Three times Berdych had good looks at backhand returns on break points in the ad court; three times he couldn’t get a hold of Wawrinka’s kicker and missed it.

Wawrinka made his World Tour Finals debut in style, and he goes to 1-0 in his group, which also features Rafael Nadal and David Ferrer. Stan may not understand either of their games as well as he does Berdych’s, but another 43 winners against one of them may be enough to get him to the semifinals here.