Third-seeded Yannick Noah, the urbane Frenchman with the magnificent serve-and-volley game, and top-seeded Jimmy Connors, the base-line brawler from Belleville, Ill., yesterday advanced to a semifinal meeting in the D.C. National Bank Tennis Classic. Somehow, it seems this one should have been saved for the final.

Noah defeated fifth-seeded Aaron Krickstein, 6-2, 6-4, and Connors eliminated unseeded Jakob Hlasek by the same score at Rock Creek Tennis Stadium. The highest-ranking players left in the tournament, Noah and Connors will meet tonight at 7 o'clock in what figures to be more of a prizefight than a tennis match.

The other semifinal will match two young Argentinians. The great philosophical debate in Argentina is which player is going to be the next Guillermo Vilas. Some say it is 20-year-old Martin Jaite, a former ball boy for Vilas who advanced with a 6-2, 6-3 victory last night over Pablo Arraya. Others say Marcelo Ingaramo, 22, who defeated the great Vilas himself, a three-time champion here, in the other quarterfinal in two shockingly easy sets, 6-1, 6-4.

Jaite and Ingaramo, good friends who grew up together and often played in the tennis clubs of Buenos Aires, will meet this afternoon. Jaite is seeded 11th, Ingaramo is unseeded.

Noah, ranked 10th in the world, has suffered from a succession of injuries in the last year. Connors, ranked fourth and out of the top three for the first time in 10 years, is attempting to show the tennis world that, at 32, he is not fading.

Asked if he was ready to face Connors, Noah replied in only two words: "Oh, yeah."

Oh, yeah. What makes the match even more intriguing is that the two are frequent practice partners. They have worked out together every morning this week.

"I don't know what we'll do today," Noah said. "We'll have to figure something else out."

Noah and Krickstein had met twice before, Noah, a 25-year-old Frenchman, winning both times. The third meeting was a mix of the 6-foot-4 Noah's speed and huge serve, and Krickstein's cleverness and ground strokes. The ground strokes are what went awry for Krickstein, who, at 17, is the youngest men's player to win a Grand Prix tournament.

He was broken by Noah in the fifth and seventh games of the first set, then had a 3-0 lead in the second set disappear as quickly as he had taken it. Noah broke in the fifth and seventh games and delivered seven aces in his last three service games to win the match.

Some of the drama is taken out of today's match by Connors' 5-0 record against Noah. But clay is Noah's best surface and he seems to be returning to his form of 1983, when he won the French Open. Four of Connors' victories came before 1983, and only two were on clay.

Against Krickstein, Noah "played my best match of the tournament so far . . . This is the first week nothing is hurting me. Usually, I carry ice everywhere."

Hlasek, a 20-year-old who lists Switzerland as home but originally is from Czechoslovakia, had never played Connors, who looked a little sharper than he had in his first two matches, against Stefan Eriksson and Michael Pernfors.

"I played well, better than my last two matches," Connors said. "The other two (opponents) hit more topspin, this one played me lower. I had to dig out a few shots. But that's good; now I've played all kinds. Nothing can surprise me."

Connors broke serve in the fourth and seventh games of the first set and the fourth game of the second set. Hlasek, who displayed only a big serve and large but erratic forehand, never threatened.

Vilas, appearing listless, seemed overpowered by Ingaramo's deep, looping topspin strokes. He was broken in the first and sixth games of the first set and the first game of the second set. Ingaramo extended his lead to 3-1, but Vilas had a few good games left. He held serve at love and that seemed to give him a lift, because he finally broke serve for the first time to put the set back in order at 3-3.

Vilas then took his only lead of the match, holding serve on two topspin errors by Ingaramo, one forehand and one backhand. But Ingaramo replied with a relatively easy break in the ninth game and served out for the match. He killed a break point with an ace, then had a match point when Vilas missed an easy forehand putaway.

Vilas saved it with an extended rally that ended with Ingaramo's forehand in the net, but the younger player attacked the net and came up with two easy volleys for the match.

"He didn't have much to lose, so he played very loose," said Vilas, unseeded but a decisive favorite over Ingaramo. "Any player from Argentina who beats me must feel something interesting. I would like to beat me, too, if I were in their places."

This wasn't the first time Ingaramo had beaten Vilas. They met last year in Barcelona, Ingaramo winning in the third round, 6-3, 6-2. He is the only other Argentine beside Jose-Luis Clerc to have beaten Vilas.

"I think my game doesn't like him," he said. "I just tried to attack him . . . He is my hero, so it is very difficult to see him on the other side of the net. I did get a little nervous in the second set."

Ingaramo will have another emotional match today against Jaite. They have met twice in satellite tournaments, Jaite winning both. While Ingaramo is ranked only No. 122 in the world, Jaite is 27th and seeking his second straight final. He lost to Mats Wilander in the final of the U.S. Pro Championships last week.

Jaite had a relatively easy time with Arraya, who spent much of his time complaining about line calls and was given an official warning by chair umpire Zeno Pfau for an audible obscenity after Jaite took a 4-0 lead in the first set. Jaite broke three times in the first set and twice in the second as Arraya never appeared to be fully in the match. t-victory set over Aaron Krickstein at Rock Creek Tennis Stadium;