Swirling winds and rain made playing conditions difficult today in the French Open tennis championships, but defending champion Bjorn Borg moved into the fourth round with his third straight easy victory.

Borg, who will celebrate his 24th birthday Friday, is seeking an unprecedented third consecutive singles title in the world's premier clay-court tournament.

Today, he played with his usual machine-like efficiency, despite distracting and trying conditions, eliminating Pascal Portes, 6-3, 6-0, 6-1.

Borg has lost only 17 games in routing Alvaro Fillol, Andres Gomez and Portes -- a dream draw so far for a major championship -- and said afterward he would have welcomed a stiffer test.

"I've had three easy matches. I don't know if it's good or not . . . It might be difficult later if I have a really tough match, because I won't be used to it," said Borg, who in 1978 cruised through seven matches at Stade Roland Garros here, losing no sets and only 32 games.

'I've been playing well -- not very, very well, but I'm satisfied," he added, trying to be charitable. "I don't think my opponents have been bad."

Borg played steadily and safely today, trying to keep the ball in the court and avoid the vagaries of the wind. Portes had much more trouble handling the conditions, making unforced errors by the dozen.

In off-the-court news, John McEnroe, ousted Friday in the third rould by Paul McNamara, had the added indignity of being hit with a $1,250 fine today for his ungraceful exit, in which he made an insulting remark to the umpire and an obscene gesture to the crowd.

Among those advancing to the fourth round were Balazs Taroczy, Borg's next opponent; Peter McNamara, Corrado Barazzutti, and Manuel Orantes. Only McNamara lost a set, to Christophe Roger-Vasselin.

Billie Jean King, Wendy Turnbull and Dianne Fromholtz, and 1978 champion Virginia Ruzici reached the women's quarterfinals.

King played the opening match on center court, defeating Leslie Allen, 6-4, 3-6, 6-2.

The match was delayed four hours by rain, and the wind was blowing in cold, uncomfortable gust, whipping up storms of red clay dust and playing havoc with the ball.

This was Roland Garros at its most somber -- the sky a metallic gray, the chestnut trees bending in the wind, the flags stop the stadium stiff in the brisk breeze. Spectators were shivering, bundled up in overcoats and scarves, and looking like so many characters out of 'Les Miserables."

The wind whipping into the umpire's microphone created a distracting static. Debris flew on the court, and dust into the eyes of the players. "The best strategy in this weather," a courtside onlooker said through lips turning blue, "is to just keep the ball out of the hurricane."

Both King and Allen -- a 5-foot-9, lanky, aggressive player who is the daughter of a Broadway actress and one of several young black players on the women's circuit -- battled the conditions as much as each other.

King, the 1977 champion and the No. 2 seed, said the conditions were among the worst she had ever played in. "I remember one Wightman cup match in 1961, in Chicago, and a tournament in Tasmania in the mid-60s," she said. "This has to be about the third worst."

Variable conditions are one factor that make the French such a difficult tournament to win. Slow, red clay is a demanding surface to begin with, and Paris in the springtime -- despite its many charms -- is not known for two-week stretches of good weather.

Guillermo Vilas, the only player to beat Borg on clay since 1976 -- earlier this month on Dusseldorf, ending Borg's 98-match clay streak -- led Buster Mottram by two sets to love when rain suspended play for the evening.