Martina Navratilova, the world's No. 1- ranked woman tennis player, has entered the Virginia Slims of Washington tournament that will be played at George Washington University and Capital Centre Jan. 3-8.

Seven of the top 10 players in the world have entered, including No. 3 Andrea Jaeger, No. 4 Tracy Austin, No. 5 Pam Shriver, No. 7 Hana Mandlikova, No. 9 Barbara Potter and No. 10 Sylvia Hanika.

Tournament Director Ray Benton said he expects to receive commitments from other prominent players in the next few weeks, but said yesterday that Chris Evert Lloyd, No. 2 in the rankings, almost definitely would not compete. "Chrissie traditionally hasn't played the early part of the circuit," he said. "It would be a very delightful surprise if she decided to play here." . . .

Top-seeded John McEnroe beat Henri Leconte, 6-3, 7-5, and unseeded Vince van Patten saved two match points to defeat Wojtek Fibak, 4-6, 7-6, 6-4, to advance to the semifinals of the $200,000 Benson and Hedges tournament in London. The other semifinalists are No. 6 seed Brian Gottfried, who beat Andres Gomez, the No. 4 seed, 7-6, 6-2, and Steve Denton, who ousted Tomas Smid, 4-6, 7-6, 6-4 . . .

In Adelaide, Australia, Wendy Turnbull, 30, scored one of the major victories of her career when she beat Tracy Austin, 6-4, 2-6, 7-5, on the third day of the Toyota Classic.

It was the first time that Austin's "rest of the world" team had lost even a set in the $200,000 tournament that is being run along Davis Cup lines.

Austin, Mandlikova and Shriver are playing for the "rest of the world," while Turnbull, Evonne Goolagong Cawley and Sue Barker are representing the British Commonwealth.