And yet, it was what allowed Wozniaki to eventually triumph over Kerber for the first time in their last four meetings and to advance to the Indian Wells 2013 final.
Caroline was ahead in the third and decisive set, up 3-1, but it was a pressure point, 30-all. Kerber returned with a deep backhand right at Wozniaki's feet, prompting her to react defensively with a moonball. Kerber took the high ball out of the air with her leftie forehand, hitting a sharp, cross-court angle that got yet another moonball response from Caro.
Two can play at that game, thought Kerber, and she joined in. A murmur starts to swell through the crowd: "Hey, are we watching pro tennis, or a USTA 3.0 women's league?"
Yet no 3.0 player I know, including myself, could have kept it up for a 38-shot rally. Most of the time, those high bouncers have me flailing helplessly deep behind the baseline, as I fall back into the cold embrace of the bubble.
About 20 shots into the rally, Wozniacki goes for a hard, flat cross-court backhand, but Kerber's been knocked senseless by the lack of oxygen in outer space. She replies with a moonball, setting up another rally that Kevin Ford, Evgeny Terelkin and Oleg Novitskiy might have enjoyed on the International Space Station, had they not been preparing to come back to earth today.
On center court at Indian Wells, the tennis ball's space mission finally ended when Wozniaki came up to a short sitter from Kerber and hit a flat, hard backhand deep into the deuce court to end the point.
"I think she was moving better and hit the ball a little bit higher," Kerber said after Wozniaki defeated her, 2-6, 6-4, 7-5. She admitted it changed the momentum of the match. "I was not expect these balls."
Neither did anyone else. A journalist asked her what she was thinking during the moonball rally. Was it, "I haven't played this way since I was 5"? Or, "I'm going to kill myself if I end up being out-moonballed"? Or, "God, I hope Tennis Channel took a commercial break!"
"What I'm thinking... I don't know. I try to play the point. Doesn't matter if it's high or if it's flat. It's a different style of game, but it's tennis," said Kerber.
Yes, Haters, it's tennis. Moonballs are a legitimate shot.
Or, as Caroline Wozniaki put it afterwards, "I was trying to figure out a way to win. And it doesn't really matter how."