Consider now the Boris Becker serve.
When struck, the ball travels with such speed that players who are not fortunate enough to hit it back often find solace in mere sightings.
Here is Becker serving Wednesday night against Yannick Noah.
. . .
Want to see it again?
Against Yannick it was supersonic.
Becker blasted his way into the U.S. Open semifinals on the strength of his serve and simply overpowered Noah, another of tennis' power brokers, 6-3, 6-3, 6-2.
It was easier than Becker ever thought it would be. But it was also about time. In his second-round match, Becker had to stare down two match points, and up until facing Noah, his play had been spotty.
All that changed in 1 hour 56 minutes of a high-speed chase between Noah's racket and Becker's serve. Noah never caught up.
Did he ever have a chance?
"Maybe if you put the tape of the match back at the beginning and run it slow motion," Noah said.
Becker served 13 games and never allowed Noah a break point. In fact, Noah managed only 11 points on Becker's serve in three sets of sheer agony.
"I almost didn't make any mistakes," Becker said.
Instead, he continued a remarkable stretch of success. Becker has won 26 of his last 28 matches since the French Open, losing only to Stefan Edberg in Paris and to Brad Gilbert in Cincinnati.
Becker even won 79% of his second serves against Noah, who said he was sad about being unable to handle them.
"I have seen him play some great matches," Noah said. "You need two guys to play a great match. Tonight, he was pretty much by himself out there."
Soon, Becker will be joined by Aaron Krickstein, who won the other quarterfinal sooner than expected.
Jay Berger quit in the fourth set because of leg cramps, which sent Krickstein into the semifinals against Becker, where he gets his chance to put his racket on Becker's serves.
Berger, who lost, 3-6, 6-4, 6-2, 1-0, retired, was a bit too busy feeling sorry for himself to congratulate Krickstein.
"I'm not going to say I'm happy for him because I'm not," Berger said.
His muscle problems began in his left thigh and quickly moved south: calves, ankles, feet. All at once, Berger knew the end was here.
"Every time I ran, I got cramps," he said. "It would have been absolutely stupid to continue."
Krickstein realized that something strange was going on with Berger in the fifth game of the third set. At the end of a long rally, Berger's legs seemed to give out and he went to his knees just as Krickstein sent a backhand down the line.
Berger stood up but doubled over in pain. Chair umpire Michael Loo gave Berger a warning for delay of game and instructed Krickstein to continue.
"I wasn't even going to serve, to tell you the truth," Krickstein said. "I served, but what was I going to do? I'm trying to win the match."
So with his opponent barely able to stand, Krickstein used slice serves that bounced away from Berger and forced him to run.
"I'm sure that anyone else playing me wouldn't have mercy on me," Krickstein said.
Berger did not win another point. He tried serving underhanded, but that didn't work. He wound up losing five consecutive games and retired following the first game of the fourth set, after a visit by the trainer did not help his cramps.
For Krickstein, it is his first semifinal appearance in a Grand Slam event.
"I felt that I was going to win anyway," Krickstein said. "That's the way the match was going."
Last year, Krickstein made it to the quarterfinals of the Open. He upset Stefan Edberg in the fourth round before losing to Darren Cahill in five sets.
Becker reached the U.S. Open semifinals in 1986 and lost to Miloslav Mecir in five sets. Becker, who won Wimbledon this year, also reached the semifinals of the French Open.
He closed out the first set against Noah in 32 minutes, breaking him at love for a 4-2 lead. He served an ace on set point.
The second set also turned early, when Becker broke Noah in the fifth game as the Frenchman double-faulted on break point. A brilliant backhand pass down the line set it up for Becker.
Becker served enough winners (36) and aces (three), and won so many points at the net (82% of his tries), that the Noah highlight film was short.
That would be a lunging volley that left Noah flat on his stomach. The ball flew long.
"There was not much I could hope for," Noah said.
Few listened when Becker said it was all right for him to struggle early in the Open, as he did when Derrick Rostagno twice held match points against him. But Becker came through and now he may be saving his best for last.
"When you are confident," he said, "good things will come."