Sabatini Surprised by Date : Tennis: Unseeded player, a 3-6, 6-1, 6-4 winner, meets Seles in today’s final.

Today’s tennis question is how can a player ranked No. 112, who has never even made a semifinal of a regular tour event, beat the No. 3 ranked player, who is also defending U.S. Open champion and Wimbledon runner-up?

“I don’t know,” Kimiko Date said.

So there you have it, as reasonable explanation as any for how the 20-year-old daughter of the Kyoto, Japan, subway manager managed to pull off a shocking upset of Gabriela Sabatini Saturday night in the Virginia Slims of Los Angeles.

Actually, there may be a better way to describe Date’s 3-6, 6-1, 6-4 upset at Manhattan Country Club.

Date, pronounced Daw-tay, reached today’s final against Monica Seles, who lost something the moment Sabatini sent a service return long to end it.

In something of an unusual twist, Seles’ No. 1 ranking skipped off into the darkness right along with the ball.

The only way Seles could keep her No. 1 ranking for another week was for her to beat both Arantxa Sanchez Vicario and Sabatini, but although Seles kept her half of the bargain, Sabatini failed.

Seles escaped Sanchez Vicario’s wily slow-down, speed-up trap and kept on track to retain her No. 1 ranking by pulling out a 6-7 (5-7), 6-4, 6-4 decision.

How could a qualifier make the final in a tournament that featured three of the top four players in the world--No. 1 Seles, No. 3 Sabatini, No. 4 Sanchez Vicario?

Date merely grinned. There were more smiles than answers in her post-match news conference.

She won four satellite events in 1989 and 1990, but before this week did not win more than two matches in any tournament this year.

Unaccustomed to playing a night semifinal, Date didn’t know exactly how to prepare, so did what a lot of people in Southern California do. She spent some time at a swimming pool.

And what did that do?

“It helped me move better,” Date said through an interpreter.

Sabatini struggled at the baseline, as she did in her uphill three-set victory over Lori McNeil in the quarterfinals, but she refused to blame her serve.

“That’s something that has nothing to do,” Sabatini said. “I just got tired.”

Nevertheless, Sabatini never was able to hit her serves consistently hard, enabling Date to hit deep returns and dictate the points even when she was receiving.

Seles’ victory over Sanchez Vicario was pockmarked by 14 service breaks, enough disputed calls to fill a racket bag and interrupted by a series of shouts from the stands during play.

Once someone yelled from the seats as Seles began to hit a ball. Needless to say, she was distracted.

“I don’t know what (he was) saying, but I don’t think he was yelling nice words,” Seles said.

Sanchez Vicario devised a game plan of changing the pace on the balls she hit, from slow to slower to fast, which kept Seles off-balance almost as much as a few other self-induced factors.

Actually, Seles had her hands full trying to plow through distractions more her own doing.

She held four set points to win the first set and blew them all, trudged to a tiebreaker, fell behind, 0-3, double-faulted at a critical point, then lost the tiebreaker when she unwisely followed in an average first serve and watched Sanchez Vicario crushed a forehand passing shot in the corner.

“The serve I think was working pretty badly today,” Seles said.

Luckily for her, the Sanchez Vicario serve was working even worse. Seles evened the match when she scored a key service break for 4-3 as Sanchez Vicario double-faulted at 15-40.

In the third set, there were five service breaks in the last six games, the last when Sanchez Vicario served at 4-4.

There were 104 unforced errors, 58 by Sanchez Vicario. She fought off one match point before Seles scorched a two-fisted backhand winner down the line to end it after 2 hours 18 minutes.

Tennis Notes

The last time a qualifier reached the final of a women’s pro tour event was the 1989 Suntory in Japan, a $100,000 tournament, when qualifier Kumiko Okamoto defeated Liz Smylie in the final. . . . Win or lose in the final today, Monica Seles will slip to No. 2 in the rankings behind Steffi Graf. To retain No. 1, she needed the bonus points from defeating No. 3-ranked Gabriela Sabatini, but Date beat her to it.