The departure of aging Guillermo Vilas was scheduled to occur simultaneously with the ascension of 22-year-old Henrik Sundstrom, the seventh-ranked player in the world just two years ago and one of the half-dozen Swedish players expected to dominate the men's game over the next five years.

But the twists their careers have taken were never more evident than in Vilas' 6-4, 6-2 victory over Sundstrom yesterday in a second-round match of the Sovran Bank/D.C. National Tennis Classic at Rock Creek Tennis Stadium.

There was Vilas, his 34th birthday three weeks away, continuing to play some of his best tennis in the last five years, attacking as he rarely did in his prime and performing with the confidence of a man 10 years younger.

Meanwhile, unseeded Sundstrom struggled with his strokes and his confidence, and talked of perhaps regaining his game by 1987.

The resurgent Vilas, the No. 4 seed in this event, is regaining his right now. From the final two points of the first set, until he took a three games to none lead in the second, Vilas won 14 of 16 points. The rest was easy.

Other players who advanced yesterday were top-seeded Andres Gomez of Ecuador, third-seeded Martin Jaite of Argentina, sixth-seeded Kent Carlsson of Sweden, ninth-seeded Aaron Krickstein of Grosse Pointe, Mich., 14th-seeded Pablo Arraya of Peru and 15th-seeded Ronald Agenor of Haiti.

Gomez, No. 10 in the world and coming off a victory in last week's U.S. Pro championships, beat Dan Goldie of McLean, 6-3, 6-3. Gomez broke Goldie twice to win the first set and survived a brief scare when Goldie broke him to tie, 3-3, in the second. After forcing Goldie to deuce in the next game, Gomez broke back. He then held at love and broke Goldie for the match.

The second seed, Thierry Tulasne of France, kept this from being senior citizens' day when he came from behind to defeat crowd favorite Harold Solomon, 4-6, 6-3, 6-1.

Solomon, a month younger than Vilas, played inspired tennis in winning the first set. He had a chance to tie the second set at 4-all, but could not make the most of three break points. It appeared he would have a fourth break point but he missed with a drop shot when a routine overhead would have won the point.

That unforced error gave Tulasne a 5-3 lead. The 23-year-old Frenchman broke Solomon at love to win the second set, and had almost no trouble in the third, despite being broken in the first game.

But the most glamorous matchup of the tournament to date was clearly Vilas-Sundstrom, two of the few legitimate stars the tournament has to offer. Sundstrom was ranked No. 7 in the world two years ago when he defeated John McEnroe in a Davis Cup match.

And Vilas spent most every day of a nine-year period (1975-1983) ranked in the top six.

Vilas, after falling out of the top 30 last year, has risen to No. 22 on the strength of recent performances. But Sundstrom has dropped to 78th in the world and is trying to shake himself out of an 18-month slump.

Sundstrom's tactic yesterday was to gamble. Go for aces and winners and try to prevent Vilas from getting into one of his hypnotic, base line trances that few players can handle when the surface is clay.

When Vilas paid virtually no attention to the Swede's attempts at aces and winners, Sundstrom pretty much fell apart.

"When you play Guillermo on clay, you know it is going to be a very long match," Sundstrom said. "I didn't want to let him be out there all day. He's very strong. I tried to speed up the thing a little. But he's steady still. He attacked more than I thought he would.

"It's really something for him to keep up play the way he has. He could be only a few weeks away from being right up there again."

Vilas ran Sundstrom from side to side, coming to net to put away volleys and overheads when necessary, usually on the key points. Sundstrom's gambling paid off in the first game when he served two aces. But Vilas won the next three games, including one service break, to take a 3-1 lead.

Leading, 4-3, Vilas attacked twice in one game -- something he never would have dreamed of 10 years ago -- and won with volleys that led to the first-set victory.

Vilas broke Sundstrom to win the first game of the second set, then simply crushed Sundstrom in taking a 5-1 lead.

Sundstrom netted a routine forehand to fall behind, 30-15, and blew a rather ordinary backhand overhead to end the match. He clearly, at least for now, is not the player who just years ago was said to be perhaps the best of four Swedes (the others being Stefan Edberg, Joakim Nystrom and Anders Jarryd).

"To have so much success and then start to lose, you get down," Sundstrom said. "I'll have to work very, very hard to get it back. And it's not easy."

But Vilas said, "When he was No. 7 in the world, nobody knew him. People got used to him and knew what to come up with. That player has to come up with new answers . . . .

"Sometimes, the young guys go up in the rankings and then they disappear," Vilas said.

Sundstrom hasn't disappeared, but he is getting harder and harder to see.

He has been passed by such players as Jaite, now ranked 16th in the world, who yesterday beat Brazil's Cesar Kist, 6-2, 6-3; 18-year-old Kent Carlsson, the 23rd-ranked player in the world, who beat Jay Berger, 6-1, 6-2; and Krickstein (39th in the world) who defeated Andrew Sznajder of Canada, 6-3, 6-4. TODAY'S SCHEDULE Stadium Court at noon

Kent Carlsson (6), Sweden, vs. Jorge Arrese, Spain; followed by Aaron Krickstein (9), Grosse Pointe, Mich. vs. Marko Ostoja, Yugoslavia; followed by Fernando Luna (16), Spain, vs. Andres Gomez (1), Ecuador; followed by Jimmy Arias, Jericho, N.Y.-Blaine Willenborg, Miami Shores, Fla. (5) vs. Dan Cassidy, Hollywood, Fla.-Mel Purcell, Murray, Ky. Court A-2 at 1 p.m.

Johan Carlsson, Sweden, vs. Marty Davis, Alameda, Calif.;followed by Jimmy Arias (5), Jericho, N.Y., vs. Horacio de la Pena, Argentina (12); followed by Rill Baxter, Sarasota, Fla.-John Ross, Gainesville, Fla. vs. Libor Pimek, Czechoslovakia-Milan Srejber, Czechoslovakia. Court A-4 at 1 p.m.

Michael Robertson, South Africa-Tomm Warneke, Lakeland, Fla. (3) vs. Ricky Brown, Largo, Fla.-Ted Erck, Houston; followed by Ronald Agenor (15), Haiti vs. Thierry Tulasne (2), France; followed by Barry Moir, South Africa-Jorgen Windahl, Sweden, vs. Ricardo Acioly, Brazil-Cesar Kist, Brazil. Stadium Court at 7 p.m.

Martin Jaite (3), Argentina, vs. Pablo Arraya (14), Peru; followed by Guillermo Vilas (4), Argentina vs. Karel Novacek, Czechoslovakia. Court A-2 at 7:30 p.m.

Dan Goldie, McLean-Kelly Jones, San Diego, vs. Gary Donnelly, Phoenix-Robert Seguso, Prairie Oaks, Fla. (2); followed by Andres Gomez, Ecuador-Hans Gildemeister, Chile (1), vs. Jay Berger, Fort Lauderdale, Fla.-Richey Reneberg, Houston. Court A-4 at 7:30 p.m.

Jorge Lozano, Mexico-Patrick McEnroe, New York vs. Ronald Agenor, Haiti-Marko Ostoja, Yugoslavia; followed by Tony Mmoh, Nigeria-Randy Nixon, Coronado, Calif. vs. Jonny Levine, Phoenix-Christo Steyn, South Africa. *All afternoon matches subject to court change.