Jennifer may be the star of the Capriati family but she is not the only one on the tennis circuit.

Brother Steven, four years Jennifer's junior at 21, made his Wimbledon debut on Friday evening in the mixed doubles and he had his big sister as a partner to guide him along.

Ultimately he needed her, but the brother-sister combination proved a fruitless one as they were beaten 6-1 6-4 by Mark Knowles and Nicole Arendt on court nine.

But they hope to repeat the partnership at the US Open and will be hoping to play more than one match there.

"I was running around to get the ball and Jennifer was saying: Tthere's ball boys here for that'. I was calling balls out and again she was saying: 'There are line judges here for that'."

"But by the end I tried to look out for her a bit and tell her what to do.

"It would have been nice if we could have made it a bit more competitive and we felt we should have played a lot better."

Steven played competitively at junior level and plays collegiate tennis while he majors in journalism and business.

He hopes to try to make it into the top 200 next year, but he admits it gives him a lot more joy to see his sister winning than gaining his own success.

Jennifer reciprocates those words towards little brother.

"For him to finally be here, though, has always been a dream of his. He wanted to become a tennis player also.

"I would give anything to give the opportunity to him play the singles, you know, be in the spotlight."

The pair practise regularly together and Steven describes himself as Jennifer's "sparring partner".

But who wins out on the practice court?

Jennifer says: "We never play where it's just all out. There's no point. It's not good for me, he serves at more than 120mph. I don't want to get injured playing against him."

Steven admits he never had any concerns about his sister when she was out of the game due to her well-publicised injury and social problems.

"I didn't worry; she's a big girl," said Steven. "She's a smart girl and if she had quit tennis, gone to school and then in to a different a job I knew she would be good at it."

More than just brother and sister, this pairing also come across as the best of friends.