The U.S. Open showdown between Serena Williams and Sloane Stephens showcased the oldest and youngest players remaining in the women's draw.
Their 12-year age gap seemed irrelevant as Williams darted and dashed around the court.
Perhaps that's because Williams benefits from lengthy absences from the game.
Due to injuries, personal issues and a lighter schedule, Williams has missed roughly two years from the tour.
The time off and slow entry into the pro circuit left Williams fresher than her opponents.
Fewer years on the road has allowed her body to remain fine-tuned enough to take advantage of the wisdom that comes with age.
In February, Williams, 31, became the oldest woman in WTA history to gain the No. 1 ranking.
Instead of tapering off, her game is flourishing. She plays like a younger woman. That's because, in court time, she is.
Williams played in only four tournaments and missed Wimbledon and the French Open in 2006.
She has missed 11 Grand Slams in her career; more than two years' worth of majors.
After winning Wimbledon in 2010, Williams cut her foot so severely she needed foot surgery. The injury, and subsequent complications, kept her off the tour for 11 months.
The pulmonary embolism Williams suffered in 2011 left her depressed. But it also kept her off the courts. She spared her joints and ligaments months of persistent pounding.
Now, while many of her contemporaries are playing in Legends tournaments, Williams is tearing up the tour. She is blowing promising teenagers off the court. Even highly ranked players, like No. 15 Stephens, are dismissed in straight sets.
Williams' time off has given her more time.
Look around today at the elder statesmen of tennis. Tommy Haas, 35, is experiencing a late surge in his career. Haas missed about two years due to hip and shoulder surgery.
Kimiko Date-Krumm, 42, took 12 years off. Last month, she became the oldest woman in Wimbledon history to reach the third round.
Of course advances in nutrition, medicine and training have helped many athletes extend their careers.
But tennis is a grueling sport. The tour gets longer every year. Without time off to refresh or recharge, players burn out.
We've seen players like Caroline Wozniacki and Dinara Safina, who chased points and the No. 1 ranking. They entered any and every tournament. In the process, they wore themselves out.
We see the great Roger Federer, 32, looking a step slower and a bit weary on the court. Federer is only a month older than Williams.
No wonder Williams has more spring in her step.
Williams has always been a high-performance machine. But even the best built machines succumb to wear and tear.
Not Williams. Not yet.
Against Stephens, the sporty, speedy newer model, Williams outperformed.
That's because unlike some of her contemporaries, who drove their bodies into early retirement, Williams has fewer miles on her and more gas left in the tank.