It’s hard to imagine where women’s tennis stars Venus and Serena Williams might be today had it not been for mentors such as fellow American Zina Garrison.The multiple Grand Slam mixed doubles champion and women’s doubles Olympic gold medallist helped to inspire the Williams sisters to soar to even greater heights than herself.Asked whether she considers herself an inspiration for players such as the Williams sisters, Ms Garrison, a headliner in next month’s Elbow Beach Celebrity Tennis Classic, replied: “Now I do because I’m older. It’s kind of interesting because I’m starting to get back out there a little more but Venus and Serena have been around for so long that a lot of people don’t even know that I played.“But it’s just great to sometimes sit back and think about some of the things I’ve did and know that I have touched others’ lives to go on and be better than I was. It’s definitely a good feeling.”Ms Garrison, 49, has a long history with the Williams sisters who captured gold medals in women’s singles and doubles at this summer’s London Games.“I was their Fed Cup [Federation Cup] captain and also coached them at the [2008] Olympics,” she said. “I was also Serena’s mentor for years when she was on the circuit.“The WTA [Women’s Tennis Association] has a mentoring type of thing were they bring rookies in so for seven or eight years I mentored her. But I’ve known them since they were seven or eight and it’s just been great to watch them grow, not just as tennis players, but also as women.“I know that I have touched their lives and when I talk to them today they don’t ask questions, especially Serena. It’s just nice to know that you can still touch them.”Ms Garrison has given much back to the sport in terms of coaching and mentoring at the grass roots level since retiring from playing professionally in 1996. She presently runs the Zina Garrison All-Court Tennis programme in her native Houston which supports inner-city tennis.“After I finished Fed Cup and the Olympics I started giving back more to helping kids,” she said. “Actually my love [for the game] came back through helping adults and from there I realised I had a lot to give and that I had a lot of wisdom that I wasn’t giving back and that I wanted to go back and start helping.”During her 14-year professional career Ms Garrison won mixed doubles titles at Wimbledon in 1988 and 1990 and the Australian Open in 1987. But, to her everlasting regret, she never won a Grand Slam singles title.“As a pro in any sport you would like to make the Hall of Fame and you can always seal the deal by being a Grand Slam champion,” she said. “That’s the disheartening part to know that I probably won’t make the Hall of Fame because I never won a Grand Slam singles title.“But other than that I know I have touched a lot of lives so that kind of brings it back up and I have an Olympic gold medal [doubles] and bronze medal [singles] and no-one can ever take that away from me.”The closest Ms Garrison came to winning a singles Grand Slam title was at the 1990 Wimbledon Championships, where she lost to Martina Navratilova in the final. En route to her only Grand Slam singles final the American toppled world number one and defending champion Steffi Graf and reigning French Open champion Monica Seles.“It was amazing because I remember the week before I was playing horrible and I just decided to go out there and lay it on the line and things just started clicking for me,” Ms Garrison recalled. “I had a sports therapist, a nutritionist and everybody in my corner and I knew I put in the work.“I knew I could be beat those people if I played the way I knew I was capable of playing. It just started happening for me and then I had to play Martina in the final who I had only beaten once out of 33 times and I’m like ‘Of all people to have to play in the final’. I always get reminded that I’m the one Martina won her ninth Wimbledon title against.”I came up in a time of true champions that dominated, whether it was Martina, Chris [Evert], Steffi or Monica. If I came up in this era I probably would’ve at least been number one. Even without winning Grand Slams people are number ones.”