Andre Agassi and Brad Gilbert won multiple Grand Slam titles together during their partnership. (Getty Images)

In 2014, Nick Bollettieri was inducted into the International Tennis Hall of Fame in the contributor category for his work developing the games of numerous professionals as a coach. 

He’s far from the only person working behind the scenes that have guided their players to near-legendary accomplishments on the court. Here’s several coaches who’ve shaped the game through their charges and deserve a spot in the Hall of Fame through their work. 

Brad Gilbert

Running into each other during dinner back in the early 1990s, Andre Agassi asked his older countryman and rival Brad Gilbert what he thought of his game. Gilbert—who never went into a match without a game plan, an approach that took him to No. 4 in the world—laid out what he thought Agassi was doing wrong and what he should do to maximize his out-of-this-world talent. A casual conversation turned into a partnership that saw Agassi reach the top spot in the rankings and win multiple Grand Slams. After their run ended, Gilbert linked up with another young American, Andy Roddick, who dominated the summer of 2003, culminating with the title at the US Open. Though he didn’t capture a major during his playing days, Gilbert clearly showed he knows what it takes to win one from a coaching standpoint.

Richard Williams and Oracene Price

It’s one of the most widely recognized images in tennis: the sight of Richard Williams with a giant shopping cart of tennis balls to feed to his young daughters Venus and Serena. From those humble beginnings on the public courts in Compton, Calif., the sisters have transcended tennis to become international icons. While their parents, long separated, didn’t have world-class playing experience, Venus and Serena give full credit to Williams and Price—still in the stands for her daughters’ matches—for developing their games.

Melanie Molitor

A former tennis standout in her native Czechoslovakia, Melanie Molitor had grand designs for her daughter, Martina Hingis, from an early age while guiding her and developing her game. At 12 years old, Hingis won the 1993 girls’ French Open and nearly four years later, she captured her first major on the adult circuit at the 1997 Australian Open. That campaign would be one of the best in tennis history as the teenager came within a match of securing the calendar-year Grand Slam. Molitor helped Hingis see angles on the court few others could, countering more aggressive and stronger players for several years and ensuring a spot for her daughter among the all-time greats.

Paul Annacone

In Pete Sampras’ camp while the young American was being coached by Tim Gullickson, Paul Annacone took over the lead role full-time after Gullickson’s unfortunate passing. Having won four Grand Slam titles with Gullickson, Annacone guided Sampras to nine more for a total of 14—a once-thought-of unsurmountable record among the men. Annacone later linked up with Roger Federer, and was in the coach’s box as the Swiss won back-to-back ATP Finals in 2010 and ‘11, and Wimbledon in 2012.

Toni Nadal

It’s the attention to the finer details displayed by Toni Nadal that have had an impact on men’s tennis. After all, his most famous charge—Rafael Nadal—is naturally right-handed, but his uncle taught him to play with his left hand leading the way, creating some of the heaviest groundstrokes ever seen in the game. That and an indomitable will to win instilled and nurtured by the elder Nadal, have taken Rafael to a career Grand Slam, Olympic Gold medals and Davis Cup titles, and helped him establish his credentials as the greatest male player to ever step on a clay court.

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