Stats show Venus playing better ball than sister Serena

NEW YORK -- Venus and Serena Williams had banner days at the US Open on Saturday with neither of them losing a set. They lost a combined total of just nine games. (Serena beat Madison Keys 6-3, 6-3, while Venus finished up quickly, taking out Anett Kontaveit 6-2, 6-1). The Williams sisters spent a grand total of 1 hour, 58 minutes on the court.

Let's look at five takeaways from their persuasive performances:

1. Serena Williams, who's now three wins shy of completing the first calendar-year Grand Slam in 27 years, met her sternest challenge yet with her most commanding tennis.

Keys, the No. 19 seed, was regarded as the one player who could match Serena serve for serve, and the way Williams had been struggling with her own serve in recent matches only made Keys appear more threatening. But Serena won the war of the service box in a rout. Fifty percent of the serves she hit went unreturned compared to just 33 percent of Keys'. Serena had six aces to Keys' two and three service winners to none by Keys.

2. Venus hasn't been in such a positive, upbeat mood at a Grand Slam in a long time. And no wonder. She hasn't been this far at the US Open since 2010. Her cheery disposition and success are partly the result of a decision to rein in her perfectionist gene.

"It's been great," Venus said in her news conference after she advanced. "Today definitely was my highest level; the last round was pretty high, too. I just try to focus on the good things and try to not be too hard on myself. You have to really give yourself a pat on the back for the good things. As a professional athlete you're always going for perfection, but it's not always realistic."

3. Serena may have turned the corner in her weeks-long battle with the pressure attendant to her quest. Granted, she struggled in the first two sets in her third-round match with Bethanie Mattek-Sands, but that was partly because Mattek-Sands is a superb competitor whose aggressive game is ideal for taking advantage of a player who's off to a slow start.

Against Keys, however, Serena played with calm purpose, suggesting the level of stress has stabilized. After defeating Keys, Serena repeated the mantra she's been reciting all week: "I don't really feel like if I win [or lose] this tournament it's going to make or break my career." She added that she hasn't felt significant pressure since her second-round match -- and against Keys, Serena played like she believed it.

4. Venus didn't give up much ground to Serena if you compared their fourth-round stats, not even in the serving department. Forty-five percent of Venus' first serves weren't returned compared to 50 percent for Serena. Serena's fastest first serve of 121 mph was just a single mph faster than Venus'. Venus won 84 percent of her first-serve points -- five percentage points better than Serena.

Venus hit 15 winners, just 3 fewer than Serena, and she made just three more unforced errors, 9 to 6. In other words, Serena had an edge in every department, but it was slight. Of course, Serena was playing a seasoned, dangerous opponent while Venus dueled with the Estonian qualifier Anett Kontaveit.

5. Serena is genuinely worried about playing Venus in the quarterfinals. It's easy to dismiss either sister's flattering comments about the other as just sisterly log-rolling, but the greater reality is tennis is a pretty secretive game, yet there are no secrets among tennis siblings. The Williams sisters must feel vulnerable to each other, and by now, they also have gone through the entire cycle of reactions and emotions created by the challenge of meeting each other. Which means they're free to swing away and compete intensely.

Serena leads 15-11 (8-5 in majors) against Venus. While Serena has won six of the past seven meetings, she's 1-1 in the most recent matches. No active player has anything like a comparable record against Serena, which is another proof she wasn't just blowing smoke.

"I'm playing, for me, the best player in the tournament, and that's never easy," Serena said. "She's beaten me so many times. I've taken a lot of losses to her -- more than anybody. So yeah, she's a player who knows how to win, knows how to beat me, knows my weaknesses better than anyone."

Believe it when Serena added, "[Venus] is doing well and she wants to win this. So do I. It's not easy."