John McEnroe defeated Henri Leconte, 6-2, 6-3, yesterday to give the United States a final 4-1 margin over France in the Davis Cup championship series in Grenoble, France.

McEnroe's 26th victory in Davis competition left him one short of the American record held by Arthur Ashe, current nonplaying captain of the team.

Yannick Noah salvaged a match for France by routing Gene Mayer, 6-1, 6-0.

That made the series 3-1, and it was left to McEnroe to finish off the series against Leconte, the brilliant but erratic 19-year-old left-hander.

"I feel more responsibility playing Davis Cup now than I did when I started," McEnroe said, "because I have to carry the team a little bit" . . .

Martina Navratilova, the world's top woman player, lost a set for the first time since the U.S. Open, but went on to defeat Evonne Goolagong, 6-0, 3-6, 6-1, in the final of the New South Wales Open in Sydney, Australia.

The victory was Navratilova's 14th in 16 tournaments this year and the first prize of $22,000 brought her year's winnings to $680,000 . . .

Defending champion Vitas Gerulaitis won the $300,000 South African Open, downing top-seeded Guillermo Vilas, 7-6, 6-2, 4-6, 7-6, in a 3 1/2-hour match in Johannesburg.