For the second consecutive afternoon, scattered showers, interspaced at maddeningly regular intervals, today played havoc with the schedule at the Wimbledon tennis championships.

Martina Navratilova and Tracy Austin, the dominant figures in women's tennis this year, won their first-round matches easily, but only nine other women's singles and seven men's singles were completed.

Thus, after two days of the championship fortnight, the schedule is backed up by approximately 90 matches, 58 of them in singles. Tournament referee Fred Hoyles said he is not worried yet, but if more rain falls Wednesday -- as is forecast -- it may be necessary to move up the starting time later in the week a couple of hours from the traditional "2 p.m. precisely."

Navratilova and Austin, who played the first match on Centre Court and Court No. 1, respectively, both had easy matches that were dragged out by rainy delays.

Navratilova, who is seeking to become the first woman to win three successive singles titles since Billie Jean King in 1966-68, moved cautiously on the slick turf in overwhelming Ilana Kloss, 6-08, 6-2.

Austin, the reigning U.S. Open champion, who, at 17, feels she has a real chance to win at the All England Lawn Tennis and Croquet Club for the first time, came to the net more than usual in dispatching tall and agressive Californian Alycia Moulton, 6-1, 6-2.

The top men's seed to play today was No. 5 Roscoe Tanner, last year's runner-up to four-time champion Bjorn Borg. Tanner routed Jiri Hrebec of Czechoslovakia, who has never been comforatable on grass, 6-2, 6-0, 6-4.

Wojtek Fibak, the No. 13 seed who saved three match points in the fourth set against Austrailian Mark Edmondson Monday evening, had to serve for the match three times today before finally winning, 5-7, 6-4, 3-6, 7-6, 10-8.

One of the special moments of any Wimbledon is the first appearance of the defending champion, who traditionally plays the opening match on Centre Court. There is a delicious sense of renewal as the champ and first-round opponent stride onto the most celebrated court in the world with an armful of rackets and towels and turn to bow or curtsy to the royal box. The great arena swells with applause.

For the second day in a row, this ceremonial occasion was delayed by the elements. Monday, Borg's match against Ismail el Shafei was a few minutes late in starting, and today the Navratilova-Kloss match didn't get on court until nearly an hour behind schedule.

Thereafter, it didn't take long for the champion to hit stride, however, Navratilova needed only 14 minutes to win the first set from Kloss, 24, a South African left-hander who has ballooned in the last few months and looked slow and terribly out of shape.

Both players were tentative in their footwork at the outset, but Kloss looked downright clumsy and had great trouble getting down to handle the skidding bounces off the wet grass.

As Navratilova's mother and stepfather chain-smoked in the competitor's guest box and her 17-year-old sister, Jana, chomped on a mouthful of gum, the champion played a nicely controlled serve-volley game and lost only eight points in the first set.

Kloss finally showed some resistance in the early games of the second set, but lost her serve for 2-4 and seemed only to want to get the agony over with when rain came with Navratlova serving at 5-2. Navratilova lost one point on a net cord ball she couldn't pick up, then the skies opened. The players ran to the sideline to pack up their rackets, then sprinted off the court -- perhaps the fastest either had moved all afternoon.

After a delay of 71 minutes during which the tarpaulin was removed several times, only to have a drizzle start again just when the court seemed almost playable -- Navratilova lost her serve, then broke Kloss again to close out the match. The total playing time was only 34 minutes, but the elapsed time was well over two hours.

Navratilova bypassed the women's clay court circuit in Europe this spring, and was upset by Betty Stove in the third round of a tune-up grass court event at Eastbourne last week, leading to speculation that she has not had enough preparation or match play for a successful title defense.

She downplayed this today. "I had less practice on grass than last year, but more than the year before," she said."I don't think one or two more matches at Eastbourne would have mattered, because I practiced a lot after I lost there.

"I've played a lot this year, so I don't think what I've done the last couple of weeks will matter, matchwise. I feel very match-tough. I was very confident today, and hitting the ball pretty sharply."

Navratilova, 23, looks fit and trim at 144 pounds -- "the lightest I've been in about seven years." She also is unquestionably eager to win for a third time.

"My desire to win here seems to be getting greater and greater," she said. "Now that I know what it tastes like, what it feels like, I just want to keep winning. Once you start winning, you want to keep on."