To pull off a truly major upset in big-time tennis, one that the winner thinks and talks about for years afterward, takes a combination of luck, brilliance and consistency.

Yesterday, Jimmy Arias and Todd Witsken had a chance. Both have been there before, so they know what it takes. But yesterday, both failed because they lacked item three: consistency.

Their errors in the crunch allowed top-seeded Ivan Lendl and third-seeded Jimmy Connors to survive, reaching their appointed matchup in tonight's Sovran Bank/D.C. National Tennis Classic semifinals with three-set victories.

Connors, playing in brutal midday heat for 2 hours 22 minutes, limped home a 6-3, 2-6, 6-2 winner over Witsken, commenting afterward, "I'm either going to leave here in great shape or dead." Lendl, who was almost done in by the heat Thursday, played in the relative cool of the evening but needed a late barrage of Arias errors to win, 6-3, 4-6, 6-4, after being up a break in the second and third sets and not being able to finish his task.

The other quarterfinal winners yesterday, second-seeded Boris Becker and fourth-seeded Brad Gilbert, didn't have anything resembling the trouble Lendl and Connors did. Neither man lost his serve once, Becker cruising past Jay Berger, 6-3, 6-2, while Gilbert got one break in each set and eased past unseeded Marty Davis, 6-4, 6-4.

"When Jimmy {Connors} came off the court, I shook his hand right away," Becker said. "He stayed out there so long; it wasn't nearly as hot for me when I went out there."

When the long day was finally over -- the start of evening play was delayed 45 minutes because the afternoon session ran so long -- the semifinal matchups were exactly as expected: Lendl-Connors and Becker-Gilbert. This was a top-heavy field to start with -- three of the world's top six but only four of the top 25 and eight of the top 60. The top four seeds making the semifinals is hardly a shock.

Yet, Witsken and Arias came close. Witsken, 23, a lean and lanky player from Carmel, Ind., upset Connors last year in the U.S. Open on this same hardcourt surface -- DecoTurf II. Witsken has struggled since, his ranking dropping from 46th at the end of last year to 73rd this week. Making the quarterfinals here is his best performance of the year.

It could have been even better. Connors won the first set easily, breaking in the first and last games. The on-court heat, which reached 104 degrees, was stifling, the humidity hanging over the court like a blanket. Only outright, blistering winners drew any reaction from the crowd because the very act of moving to applaud was almost painful.

Connors has always been a good player in the heat and, even at 34, he still believes he can wear an opponent down when the weather is truly awful. He seemed to feel that way late in the first set when, after he had failed to run down a Witsken winner, he turned and yelled, "Hey, Todd, are we having fun out here yet?"

"As long as you're doing the running, we are," Witsken shouted back.

"Well, we'll just have to change that," Connors answered. He did just that, taking the set on his fourth-set point.

"You had to think about putting one foot in front of the other to walk," Connors said. "I think I was more tired mentally than physically out there because I had to concentrate to get anything done. It was one of those matches where you had to pick your spots and take advantage of your opportunities."

Actually, Connors had the opportunity to win the match easily. Up, 1-0, in the second set, he had two break points. Witsken saved one with a good serve, then the other when he lunged at a forehand and punched a backhand volley just past Connors' reach. Connors' reaction to that was to place a finger against his nose and hold it there, indicating disgust with himself.

"Right then," he said, "I felt tired. You get ahead, hit some good shots, it feels a lot hotter to the other guy. You miss opportunities, you feel hot."

That thought must have haunted Connors as Witsken rolled through the last five games of that set, finding his backhand and running Connors around. "I really had trouble with the heat in the first set," Witsken said. "I know it affected both of us out there. The second set, I think he started to get tired."

The heat was getting to both players. Connors looked drained at the end of the second set and appeared to be in deep trouble when he quickly dropped behind, 0-40, in the opening game of the last set. But he saved that game and then found a surge of energy, breaking Witsken to go up, 2-0.

"You really couldn't run on every point," Witsken said. "It was just hard to play tennis out there for both of us."

Connors is in remarkable shape for 34 but is 34 nonetheless. When Witsken broke back to 2-1 and held for 2-2, he looked like he might fold. And, when Witsken reached break point in the fifth game after Connors had blown four game points, Witsken was on the brink of pulling off the upset.

Then came the point that turned the match. Witsken's return was on the line. Several pro-Connors fans yelled, 'Out, out.' The point continued and Witsken blasted a backhand deep, yelling, "Shut up!" as soon as the ball left his racket.

"When the people started shouting, I lost my concentration," Witsken said. "I guess you could say that was a big turning point."

Indeed you could. Witsken never won another game. Connors, so tired in that game that he took to sitting down between points while Witsken wiped his racket off, got new life after he held.

"There were times out there when I thought, 'What the hell am I doing out here in this heat?' " Connors said. "But then I got the answer -- because I like it and I just played through it."

Lendl undoubtedly asked the same question in the third set against Arias. He was on his way to a routine win against a player he had never dropped a set to, when Arias, down a set and at 4-3 and a service break, ripped off three straight games, breaking Lendl twice to even the match.

"We play the same kind of game, but he just serves so much bigger than me," Arias said. "Usually it just wears me down. Tonight, I decided that every time I'd get a short ball, I'd come in."

That strategy helped, as did some wonderful passing shots that left Lendl smiling in disbelief. What's more, Lendl got sloppy with the lead and began spraying from the back court. "I think I did let down a little bit mentally in the second set," Lendl said. "But, actually, I'm not playing well enought right now to serve out a set. From 5-4 I can do it, but not from the beginning."

That proved true in the third when Lendl broke in the opening game only to have Arias break back in the sixth with a gorgeous forehand that Lendl reached, half-volleyed, saw it hit the net tape and then drop wide.

The evening crowd, much livelier in the cooler weather, was alive for Arias but Arias couldn't get to the finish. He held to lead, 4-3, thanks to four Lendl errors, but, serving at 4-all, he made two crucial mistakes at the end of long rallies -- a deep backhand and a netted forehand -- and it was over. Lendl served it out at love from there.

"I'm not playing my best, but then I doubt if Jimmy and Boris are thrilled with their tennis, either," Lendl said. "It would be wrong to peak now. If I win here, it's a bonus. If I lose, it's too bad, but that's all."

In short, Lendl wouldn't have cried if he had lost. Neither would Connors. For Witsken and Arias, the chance was there -- briefly.