Barry "Butch" Heffernan, 47, originally from Australia, molested the teenage girls "week in, week out," using their dreams of stardom as a means of control, a court heard.
Heffernan pleaded guilty to six sexual assaults against one girl.
Having worked in America before setting up the Down Under Tennis Academy in Hemel Hempstead seven years ago, Heffernan coached a number of "household names" in the past, St Alban's Crown Court was told.
He coached former champions Bjorn Borg and Martina Navratilova among others during his career.
His abuse finally came to an end when he admitted a series of charges involving two young women earlier this year.
Jane Bickerstaff, prosecuting, said that Heffernan routinely pressed himself up against one girl, described as a "promising player", on the tennis court telling her: "I can't wait until you're legal".
He later turned his attention to a second girl touching her improperly and eventually luring her to an empty a flat where he performed a series of sex acts on her, she said.
"He was able to get away with what he did because at the same time as abusing them, he was coaching them and they wanted to become better tennis players and achieve their dreams and ambitions," she told the court.
One of the girls eventually told her mother about the abuse but "clammed up" when police began to investigate.
He has been banned from working with children indefinitely.