WIMBLEDON, ENGLAND, JUNE 28 -- A bomb scare and the seating in the Royal Box were more eventful than the tennis at Wimbledon today. Martina Navratilova was forced to curtsy to Chris Evert, ensconced among the nobles, Ivan Lendl got silly, and a mysterious bag caused the temporary evacuation of three courts.

It was a lightheaded sort of afternoon at the All England Club once an unattended camera case was found to be harmless and play was resumed on the outer courts. The weather held and the second round was completed without undue trouble. There was just a pair of minor upsets as Henri Leconte and Ros Fairbank, each seeded 15th, were eliminated, and No. 4 Gabriela Sabatini needed six match points to defeat a 15-year-old.

A giggling Navratilova dipped her skirt to the Royal Box, where friend and ex-rival Chris Evert was a guest, then defeated Anne Smith for the 20th time, 6-2, 6-3. Lendl dismissed Jakob Hlasek in 78 minutes, 6-1, 6-3, 6-0.

"Tennis." Lendl shrugged. "Some go in, some go out. Golf's better."

Most players were not aware that part of the grounds was closed off while a bomb squad investigated a brown 35mm camera case that was left on the main boulevard of the club. On Monday four people were hurt when a bomb exploded at the Carlton House, a famed Tory club, and unattended bags and packages have been cause for concern.

The matches on the three nearest courts were stopped about 3 p.m. and the crowds cleared. Arantxa Sanchez Vicario told some confused observers as she left Court 4 in the midst of a doubles match, "It's a bomb," causing a nervous ripple. But the bag was removed and play resumed 15 minutes later.

David Pate was forced to leave Court 3 just as he served for the match against Guillaume Raoux, leading by 5-3 in the fourth set. He returned to end it in one more game. "I wanted to laugh," Pate said. "Anyway, it was on the other side of the court."

Clearly the seeded players were not affected by the scare. No. 3 Stefan Edberg advanced to the third round routinely over Miloslav Mecir, 6-2, 6-3, 6-2. Once, the fluid Mecir would have been a formidable opponent, ranked in the top 10 from 1985 to 1987, but he has fallen to No. 68 with a chronic back ailment and never could break Edberg's serve.

No. 13 Michael Chang made unexpectedly short work of doubles specialist and 74th-ranked Jim Pugh, 6-3, 6-2, 6-2, proving that he has recovered from a fractured hip, and that his counterpunching game can be successful on grass. The 1989 French Open champion is happier with the pressure off him and may become a factor, despite his loss in the fourth round of the French last month. He has made the round of 16 in his last five Grand Slam events, and his projected opponent in the fourth round is Edberg.

"I can relax a lot more and go out and just play, and not have to worry so much about being labeled the French Open champion," Chang said.

Lendl was on Centre Court and completely unaware of the bomb scare until he got to the dressing room and people mentioned it. "I thought they were kidding," he said. Probably nothing would have deterred him in his thoroughly convincing victory over No. 50 Hlasek.

It was Hlasek's worst loss to Lendl in eight matches, and just another example of how powerfully the top seed is playing, determined to claim the one Grand Slam event that has consistently frustrated him. "I'd like to think I can play better," Lendl said.

Hlasek was expected to be a far more difficult opponent, a silky player but with a history of injuries. Although he had lost six of their seven previous meetings, he has given Lendl fits, beating him in three sets at the 1988 Masters in New York and extending him to five sets in the WCT Championships in Dallas that year.

But Lendl has spent 13 weeks laboring to improve his grass-court game, and the work shows. Hlasek never threatened after they exchanged service breaks to open the match, while Lendl went on to break seven more times. He delivered six aces, carved out open court with smooth volleying and plagued his opponent with frustrating lob winners.

"I think a lot of things came together," Hlasek said. "He made me look bad because he played good."

Another of Lendl's obstacles was removed when the strapping but moody Leconte, ranked No. 26, was upset in five sets by Alex Antonitsch in the one stirring match of the afternoon, 2-6, 6-4, 7-6 (7-2), 2-6, 6-3. Leconte and Lendl could have met in the fourth round.

But Leconte sprayed errant volleys and could not convert on four break-point opportunities in the fifth set. Instead, Antonitsch got the crucial break in the eighth game, when Leconte played a series of loose shots. He double-faulted for 15-30, slammed an off-balance, backhand volley wide, and placed a low forehand half-volley just wide to give Antonitsch a 5-3 lead. The Austrian held serve to become the first man from his country to make it to the third round since Alfred Huber in 1955.

"I had the chance, I missed it," Leconte said. "He deserved it. Everything was not at its best."

Fairbank was victimized by a pulled thigh muscle and a 17-year-old with a big backhand in Amy Frazier, 6-4, 6-3. Another teenager proved troublesome, Anke Huber terrorizing Sabatini with her flat forehand before the Argentine emerged, 6-2, 7-6 (8-6).

Huber is a dangerous little player with close cropped blond hair who made the third round of the Australian Open in January. Sabatini was uncertain and blew several leads in the second set, including 5-2. She had two match ponts in the ninth game and three in the 10th but lost them on a series of errors, some unforced and some forced by Huber's lunging ground strokes.

Sabatini let yet another lead, 4-1, slip away in the tiebreaker. Huber won five of six points to surge to a 6-5 lead. But Huber's inexperience finally told. She drove a forehand into the net to end a lengthy baseline rally, then double-faulted to give Sabatini a sixth match point. Sabatini took it with a big forehand cross, relieved to be rid of a child who may have made her feel old at 20.

"I never thought I would lose the match. It's just as important to win that second set, so that's where I kept fighting," she said. "I think these are the most dangerous players -- they are young, they have no pressure, they just go for the shots. So you have to think about what you do."

Navratilova had no such problem with Smith, a 31-year-old from Dallas who had beaten her just once in 20 previous matches. Navratilova's task was to keep her mind on the match -- this was her first appearance on Centre Court this week -- but her thoughts kept wandering to the Royal Box. One guest was Kitty Godfrey, the Wimbledon champion in 1924 and 1926. "What years did she win it?" Navratilova wondered.

She also tried to spot Evert, who received an invitation to the box and took the Duke and Duchess of Kent up on it with her husband, Andy Mill. Asked if she thought she would ever have to curtsy to Evert, Navratilova shot back laughingly, "Hell, no."

Navratilova struggled just briefly, when she served for the match at 5-2, but Smith broke her at love. Navratilova responded with a break, driving a last volley at the baseline and Smith slicing a backhand into the net.

"Okay, this is just the second round, you don't want to get too excited," Navratilova said. SEEDS' SECOND-ROUND RESULTS MEN

Ivan Lendl (1), Greenwich, Conn., def. Jakob Hlasek, Switzerland, 6-1, 6-3, 6-0; Stefan Edberg (3), Sweden, def. Miloslav Mecir, Czechoslovakia, 6-2, 6-3, 6-2; Jim Courier (9), Dade City, Fla., def. Jason Stoltenberg, Australia, 6-2, 7-6 (7-3), 6-4; Michael Chang (13), Placentia, Calif., def. Jim Pugh, Palos Verdes, Calif., 6-3, 6-2, 6-2; Alex Antonitsch, Austria, def. Henri Leconte (15), France, 2-6, 6-4, 7-6 (7-2), 2-6, 6-3. WOMEN

Martina Navratilova (2), Aspen, Colo., def. Anne Smith, Dallas, 6-2, 6-3; Gabriela Sabatini (4), Argentina, def. Anke Huber, West Germany, 6-2, 7-6 (8-6); Katerina Maleeva (7), Bulgaria, def. Kimiko Date, Japan, 6-1, 6-4; Natalia Zvereva (11), Soviet Union, def. Gigi Fernandez, Puerto Rico, 7-6 (7-4), 6-4; Judith Wiesner (14), Austria, def. Karine Quentrec, France, 6-3, 6-3; Amy Frazier, Rochester Hills, Mich., def. Ros Fairbank (15), San Diego, 6-4, 6-3.

TODAY'S FEATURED MATCHES Centre Court

Monica Seles (3), Yugoslavia, vs. Anne Minter, Australia; Juan Aguilera, Spain, vs. Pat Cash, Australia. Court 1

Dan Goldie, Redwood City, Calif., vs. Boris Becker (2), West Germany; Steffi Graf (1), West Germany, vs. Claudia Kohde-Kilsch, West Germany. Court 2

Robin White, San Jose, vs. Jennifer Capriati (12), Saddlebrook, Fla.