NEW YORK, AUG. 28 -- So you're making your U.S. Open debut and they put you on the stadium court against Martina Navratilova. Federica Haumuller decided to just enjoy it. After she lost, 6-4, 6-0, she asked Navratilova for a souvenir and had her picture taken with the nine-time Wimbledon champion.

Haumuller, an 18-year-old Argentinian ranked No. 118, had a brief debut: 50 minutes. The high point of the match came when she broke Navratilova, trailing 1-4, with three straight winners. Afterwards she asked Navratilova for one of her trademark headbands. Then she had her father take a photo of the two together.

"That was kind of a first," Navratilova said. "She was cute about it. Her first Open and she plays her first match against me, on center court. That's about as good as it gets." Still No. 1, For Now

Stefan Edberg's first-round loss to Alexander Volkov of the Soviet Union won't cost him the No. 1 ranking immediately. His six titles this season, the most of any player on tour, gives him enough points to remain there for the moment. . . .

Steffi Graf tied Jimmy Connors's all-time record for most consecutive weeks as the No. 1 player in the world. The new Virginia Slims rankings were issued with Graf once again atop the list for the 159th straight week. Graf became No. 1 for the first time after defeating Chris Evert at the Virginia Slims of Los Angeles on August 16, 1987. Earlier this month she surpassed Martina Navratilova's record for women of 156 straight weeks. . . .

Navratilova had a theory as to why Edberg played so poorly today after such a hot streak. "Too much tennis," she said. Edberg went straight from his Wimbledon victory to Japan for an appearance, then played in four more tournaments leading to the Open. Navratilova watched his progress and told coach Craig Kardon the other day, "I bet he doesn't make it to the second week."

Today she said: "He won them all, but great. That doesn't help you at the Open. I hate to be right about it." Sound of Relative Silence

The rerouting of flights from LaGuardia Airport's Runway 13 has been favorably greeted by most players, but Zina Garrison sort of misses the noise. Garrison called the deafening roar from jets over the stadium a kind of signature of the Open, part of what makes it perhaps the most difficult of the major championships to win.

"To me that was the U.S. Open," she said. "You knew they were there, it was something you had to deal with. If you were in total tune with yourself it didn't matter. But it added the extra pressure." . . .

Monica Seles says she will move to Los Angeles from her current training home in Bradenton Fla.. Seles, the 16-year-old Yugoslavian native, says "L.A. is my type of town."

Seles, on why she is trying to tone down her cartoonish laugh and piercing grunts when she hits the ball, which have become her rather peculiar trademarks: "I don't want to go down in tennis history as the grunting and giggling Monica Seles." Another Fashion Statement

Andre Agassi made his Open debut wearing new attire from Nike. Under his black tennis shorts he wore chartreuse biker shorts of Lycra; his shirt was white, chartreuse and black mesh; he sported a new beard and flashed a new earring.