WIMBLEDON, ENGLAND, JUNE 26 -- Steffi Graf of West Germany has a number of opponents at Wimbledon, from second-seeded Martina Navratilova to French Open champion Monica Seles to 14-year-old Jennifer Capriati. But the toughest one may be the glare of publicity and controversy surrounding her family.

West German model Nicole Messner was arrested last week for allegedly plotting to extort money from Graf's father and manager, Peter, claiming he had fathered her child. The West German and British tabloids have had a field day with the story, and the former Grand Slam winner clearly has been affected by it.

Today, after defeating Claudia Porwik of West Germany in her first-round match, Graf said the reports have made it difficult for her to concentrate on tennis.

"It didn't make it easy, that's for sure," she said. "I had a tough time. But right now I'd like to think about tennis and what's going on here."

The story is likely to pursue Graf, however. In Wednesday's German magazine Stern Graf is quoted as saying she may move to the United States to escape the media pressure she feels at home. She keeps a second home in Boca Raton, Fla. Graf today sidestepped the issue of whether she might move.

"The family is very close together," Graf said. Her mother, Heidi, is at Wimbledon and her parents have made it clear they are united. "There is no doubt about that. We have always been very close and we always could talk about everything, and nothing has changed at all. I think it brought us together more maybe."Noah's Pride in Cameroon Lions

Yannick Noah consoled himself for his first-round loss to Wayne Ferreira by going to the World Cup. Noah, originally from Cameroon, is a friend of a number of the soccer players.

"We have the best sorcerers in the world. They can make magic, you know," he said. "In the different papers around the world now they have a map of Africa showing where Cameroon is. I think that's what it's all about. The last two weeks have been like a holiday for everybody. Everybody is dancing, forgetting about what problems they have. Whatever makes people feel this way, it's great. If I can do it, it's great, but what they're doing right now, it's much bigger than what I've ever done."Navratilova Is Amused

Martina Navratilova had some words for Andre Agassi, the No. 5 ranked player who skipped Wimbledon again. Agassi has not played here since a first-round loss in 1987, saying it does not fit his schedule.

"I still laugh at his reasons for not playing," she said. "This is Wimbledon. It's like a football player who skips the Super Bowl because he has to get ready for spring training." . . .

A county law on safety at sporting grounds required Wimbledon to make $2 million in alterations. There is no more standing room at Centre Court, and thus the familiar sight of fans crammed into corners and craning over parapets has disappeared. Also, British photographers are boycotting Centre Court and courts Nos. 1 and 2 because they have lost preferential assigned positions.