"Who's No. 1?' in women's tennis, asked the buttons distributed by the Colgate Series Championships promoters at a draw party here for the Jan. 2-7 Capital Centre event.

Martina Navratilova, replied the U.S. Tennis Association, by coincidence issuing its 1979 computer rankings from New York yesterday. Navratilova, echoes Tennis magazine's international ranking panel in its 1979 world appraisal.

Chris Evert, dislodged from top spot in USTA after six consecutive years on top, may have something to say about that when she visits Washington next week.

And the winner of the eight-woman draw among the point leaders from the 33-tournament 1979 Colgate Circuit certainly will have a claim on No. 1 at least through the early months of 1980. The Jan. 2 opening Centre matches for the double-elimination, $250,000 finals, $75,000 to the winner (series points in parentheses):

Afternoon (1 p.m.): Evonne Goolagong (930) vs. Regina Marsikova (615), then Navratilova (1,120) vs. Jerry Reid (660). Evening (7 p.m.): Evert (1,190) vs. Dianne Fromholtz (645), then Tracy Austin (1,020) vs. Wendy Turnbull (800).

Billie Jean King missed beating Marsikova out of a singles slot by losing in series event No. 33, last week in Sydney, to Betty Ann Stuart. But, never fear, B.J.'ll be here -- teamed in doubles with Navy against the same Stuart and Ilana Kloss in a Colgate semifinal opening night; Evert-Rosie Casals and Turnbull-Betty Stove matched Jan. 3 in the other semi.

By the time yesterday's party was over, even D.C. restaurateur Dominique and his staff wore "Who's No. 1?" buttons. Now, as to a rating for Dominique's famous rattlesnake-meat cocktail: comme-ci, comme-ca; pretty fangless . . .

Another barroom brawl story, another South Africa report, rolled up in one and bad news for Diplomat soccer followers: Dip swifty Ken Mokgojoa stabbed several times in the chest in a Krugersdorp beer hall, police report. Mokgojoa was visiting his homeland, where fans affectionately dubbed him "The Horse" before he came to Washington to make his fortune. He is due to return to the States in February, but his doctor says it is doubtful Mokgojoa will be able to play full tilt before March. Good think NASL doesn't start till April . . .

Charles White of USC is college football's player of the year, United Press International's media panel concurs with the Heisman voters; by a landslide over runner-up Marc Wilson, the BYU rifle . . . Joe Theismann is the outstanding Redskin of the year, the Quarterback club of Washington concurs with the team's MVP sentiment. And the QBers will salute Joe T at a noon lunch Monday (day after victory in the Washington-Irving battle, they hope), with Sen. John Culver (D-Iowa) making presentation and a special guest on hand in the person of U.S. Marine Sgt. William E. Quarles -- one of the hostages the Iranians let go. The sergeant went four years without getting to see a football game live, we're told. A home playoff could remedy that, hey? . . .

Even Chatterbox Joe will be hard put to talk faster than Billy Martin did night 'fore last in his first public appearance since Yankee Firing II. Says Martin of boss George Steinbrenner: "I think the man is sick . . . I'll only go back if George is gone. I won't even play in an old-timers game . . . Right at this time, I don't think I'll take any job. I think I'll enjoy George's money for two years."

Speaking, then A'ing Qs at the U. of Rhode Island, Martin "apologized" for the "marshmallow" incident that put him out of work: "I'm sorry . . . but if I had to do it over again, I'd punch that guy right in the nose . . . because he was rude . . . To this day, no one saw the punch. He really might have slipped."

About the celebrated occasion on the team bus in Chicago during which Martin and players supposedly autographed a woman's bare hind end: "She wasn't too shabby. On a scale of 1 to 10, she was about a 12 or 15" . . .