One more step and he's in the potted plants at courtside. He's running to catch a shot that nobody can catch. He'll be lucky to put the frame on it. But on the fly, reaching flat out, Ivan Lendl not only gets the sweet spot on the ball, he beats the fuzz off it. He sends a laser beam back past Mats Wilander, who can only stand and watch.

The running forehand is Ivan Lendl's signature. He is a picture of controlled shotmaking, every stroke as emphatic as it is compact. Only on the run does he make the beauty that tells us he is more than a mechanic. On the run he is an artist. Tall, lean and strong, Lendl whipping that forehand down the line creates a picture so pretty that even the coldest heart grows warm.

Not many of the folks who pay their way into the U.S. Open like Lendl. He is only 23, but there is testimony he didn't smile the first 22 years while establishing his reputation as a hard-faced grouch. Geography has something to do with the antipathy, too. It's never a good time to be from a country owned by the Soviets. Maybe it's a worse time when they shoot a plane full of people out of the sky.

So when a heavy-browed Czech, such as Lendl, plays a curly blond kid from Sweden, such as Mats Wilander, a New York crowd chooses its darling quickly. From scattered spots in the stadium today, there came cries of encouragement for Wilander. For Lendl, nothing.

That's unfair, of course, but if life were fair, sports columnists would have those blond curls. The point is, Lendl's runningforehand, plucked out of the potted plants, was such a piece of work that the New Yorkers, as if instinctively answering a startle reflex, cheered the guy like crazy.

The rest of the time, nothing. Lendl is the second-seeded player and now the likely favorite with John McEnroe gone. He was masterful in his domination of Wilander. Still, the customers here gave him only the good-manners applause expected from folks who wear alligators and polo ponies on their sports shirts.

This seemed a mystery to the assembled journalists, who in several different ways asked Lendl, "Why is it that nobody in America likes you?"

"I don't know," Lendl said to a newspaperman. "What do you think?"

Lendl smiled as he said those words. He's trying to be a nice guy these days. He now has a haircut of the punk variety, softer and zanier than the Iron Curtain Chop of years past. Though still a Czech citizen, he is as Americanized as any other $2 million a year capitalist commuter (he has homes in Connecticut and Florida, where he has fallen sad victim to golf).

When the newspaperman said it doesn't matter what a journalist might think, Lendl said, "It does. You write. I don't. It's much nicer when they like you, but what can you do?"

The newspaperman had an answer: "Defect."

Lendl's smile widened. He said to the newspaperman, "Is that what you're going to do on your next trip to Moscow?"

The Czech government takes only 20 percent of Lendl's earnings and doesn't care where he lives as long as the check arrives. These are rules made after Martina Navratilova's defection. The economic incentive to defect, then, is not much of a factor for Lendl. But he hasn't been to Czechoslovakia in a year, suggesting he has no ties there, and so everyone wonders.

As gracefully as Lendl deflected this line of inquiry today, so did he dispatch Wilander. Barely 2 1/2 weeks ago, Wilander defeated Lendl on a similar surface in Cincinnati. Any idea that the young Swede could duplicate that victory was quickly put aside today, for Lendl, who won only six points in the first nine games at Cincinnati, came out smoking today.

The tone of today's the match, as it turned out, was set on the very first point.

Wilander missed his first serve. As Bjorn Borg had trouble with the serve at 19, so does Wilander. Lendl had 10 aces today, Wilander four.

On Wilander's second serve for the first point, Lendl ran around his backhand and flat-crushed a forehand winner past the helpless kid.

There was, around the stadium, a taking-in of breath. One man's notes: "0-15, L kills 2nd with fore, oooooohhh."

Most of what Lendl didn't get done with his serve today, he accomplished with a forehand so feared that everyone sends three of four shots to his backhand. This has the effect of reducing the court to half-size for Lendl's opponents while Lendl has all of the 27 feet as his target.

Lendl's serve is more difficult than McEnroe's, according to Wilander, because of what happens next.

McEnroe comes to the net behind it. Lendl stays back. Against Lendl, you not only must return a thunderous serve; you must return it where Lendl cannot then knock the fuzz off it with a forehand. There is, as Lendl demonstrated today, almost no place safe from that forehand. Nor is it easy to know where Lendl will send the forehand, for he disguises his intent superbly.

Someone asked Wilander if the problem against Lendl is anticipating the direction of his forehand.

"Even if you know the direction," Wilander said, "he hits it so hard it's hard to do anything with it."

He spoke wistfully.