US tennis star Serena Williams hopes her African tour with elder sister Venus will encourage athletes on the continent to strive for excellence in their sport.

The pair, who have won a combined 22 major women's singles championships, are in Nigeria before heading to South Africa on Friday, in a two-country visit to promote women's rights.

"We would definitely love to see more athletes come out of Africa," Serena told journalists.

"We were able to break the mould in a sport that was just really dominated by white people and to have a face of colour that can come in and dominate (shows) it doesn't matter what your background is and where you come from," she said.

Serena, 31, has visited other African nations before, while Venus, 32, landed on the continent for the first time on Tuesday.

"I've always wanted to come here," said the elder Williams sister, adding she expected to continue taking trips where athletic competition is not the primary focus.

"When you get a little older, you start to realise that you want to help other people and that that is more important than the other dreams you may have had," she said.

They began their day with a visit to Lagos state Governor Babatunde Fashola and ran a tennis clinic at the exclusive Ikoyi Club, where they schooled a group of children in some tennis basics.

One youngster stood frozen in a wide-legged stance while Venus offered racket instruction, while another said he gradually grew more confident as the lesson progressed.

"When I played them I felt nervous at first, playing one of the best in the world," said eight-year-old Akinola Ogunleye. "Then I got used to playing them ... If they can be that, why can't I?"

The sisters will on Thursday visit a puberty education class for girls and play a head-to-head exhibition match on Friday before leaving for South Africa.

While the trip is aimed at empowering young African women and girls, Venus said she also expected to benefit.

"We're looking forward to being inspired by the young women in Nigeria and also to inspire them as well. It's a two-way street. We can learn so much from each other," she told the governor.

The roughly 80 million females in Africa's most populous country face some of the most acute gender disparities in the world, with the worst inequalities existing in the majority Muslim north.

Worldwide, Nigeria ranks 118 out of 134 countries on the Gender Equality Index, according to a British Council study released in May.

Friday's match is just a charity event, but Venus said she's looking forward to playing in front of an African crowd.

"We're very excited to play tennis here," she said. "I don't know who is going to win, but I know it will be a good match."

AFP