Blame a chair umpire named Mariana Alves for professional tennis going to the use of instant replay, because it's coming. When you screw up as badly as Alves did Tuesday night at the U.S. Open, when you make one of the biggest mistakes by a chair umpire in the first game of the third set, then follow that up by failing to overrule three bad calls in the 10th game of the third set of a Grand Slam quarterfinal televised nationally, using replay is the only obvious, even if regrettable, solution.

Serena Williams was cheated Tuesday, and we all saw it with the help of "Hawk-Eye" or "Mac-Cam," everybody except the bumbling chair umpire, Alves, who just in case you're wondering has been dismissed from the rest of this U.S. Open. She didn't just blow a call; everybody blows a call or two. She absurdly overruled one correct call to make it incorrect. So worse than being wrong, she was being a jerk.

I don't believe in conspiracies, and it would be stupid to assume any of the powers-that-be in tennis would want both Venus and Serena out of the U.S. Open because it costs everybody involved money. Fans pay to see the Williams sisters, especially Serena.

Sponsors pay to see the Williams sisters, especially Serena. The TV ratings are higher when matches involve one of the Williams sisters, especially Serena. And the only color more important than black or white in America is green. Serena Williams is the most bankable star in tennis . . . bigger than Andre Agassi, bigger than Andy Roddick, bigger for now than Russian hottie Maria Sharapova. Serena's the only player in the game who could be on "Access Hollywood" and the covers of People and Sports Illustrated.

Even so, Williams has every right to feel she was robbed, because she was. And if I were Serena I'd have gone to my chair after Alves's stupid overrule, requested to see the tournament referee (as is allowed in the rules), and waited until he came to explain how a woman could rule a ball "out" that landed not on the line, but clearly, indisputably, inside it as the lineswoman definitively called.

I don't want to hear how Serena's 57 unforced errors cost her the match; we know that. And Jennifer Capriati definitely outplayed Williams after the first set. But people play badly and win all the time. That's the true test of an athlete, particularly in an individual sport -- finding a way to win when you don't have your 'A' game. Serena concluded, quite accurately, that she buried herself by making all those mistakes. But to be cheated out of three calls in one game, the 10th and final game of the third set, speaks to unforgivable incompetence. As much as she was outplayed, if those three calls are made correctly, it's 5-5 with Williams serving in the third set. She had a whole lot of help throwing dirt on the grave. The folks at the top of professional tennis's ruling pyramid have to make sure this junk doesn't happen again.

So, welcome replay.

Look, it's an inescapable element of sports life. If we can see it at home, the linesmen or umpires on site ought to have access to the same information. It doesn't matter if replay takes time, and it doesn't matter that the lines people say the technology won't be 100 percent effective. All that matters is it's more effective than people, especially people like Alves.

Former players Luke Jensen and Patrick McEnroe, both of whom call matches now on television, have made their peace with the use of replay and said they believe replay is coming sooner rather than later. In a conversation yesterday afternoon, McEnroe said he felt it would be "good for the game."

Ironically, Capriati, the beneficiary of the bad calls against Williams on Tuesday night, told reporters in New York after her previous match, "I really think they should look into having the 'Hawk-Eye' on the umpire's chair. . . . At this level of the game, when it's so close, one or two shots can make a real difference."

Still later yesterday, defending U.S. Open champion Andy Roddick told reporters in New York, "I don't really see a lot of downside in [replay]. It would be pretty easy to have a monitor right at the side of the court. I wouldn't like to see it every time because it would get ridiculous. It would become a circus. But if you have two [challenges] during a match, I don't see a whole lot of contention in that."

And that's approximately what's going to happen. Each player should be given two challenges a set. If the challenge is upheld, you keep the challenge and win or replay the point, whichever is most appropriate. If "Hawk-Eye" or "Mac-Cam," which of course is named after John ("You CANNOT BE SERIOUS!") McEnroe, shows the linesman or chair umpire to be correct, you lose the point and the challenge.

The NFL has already laid this formula out there to be plugged into almost any sport. And as silly as it seems for tennis to give itself over to such an intrusion, the delay and the annoyance are preferable to having matches decided on calls everybody watching knows are incorrect.

This notion that human error is tolerable from officials and umpires because the competitors themselves make errors is about the dumbest argument I've ever heard, not to mention lazy. We don't watch sports to see refs and umps. If there's a way technology can instantly show us the correct call, it simply must be used. The viewing public won't stand for less, which is why the Big Ten is now using replay in its college football games.

Getting it right is all that should matter. And the current technology will get it right. In tennis, there's no judgment as there is in using football replays. There's no coordination of feet and hands, no decision on whether a receiver is juggling or has possession. Either the ball touches some part of the line or it doesn't.

In a statement yesterday, the U.S. Open tournament referee Brian Earley said, "the USTA continues to explore video technology as a future aid to officials, with tests conducted as recently as this year's U.S. Open qualifying tournament."

As Capriati said, it's time to stop testing and start using replay because tennis simply doesn't need any more episodes like the one it had Tuesday night.