The 2015 season brought faces both famous and accomplished back to the tennis coaching ranks: Lindsay Davenport with Madison Keys. Martina Navratilova with Agnieszka Radwanska. The veteran Tom Gullickson with Sam Querrey.
Perhaps the least heralded tandem, the most out-of-the-box pairing, was American John Isner with countryman Justin Gimelstob – a former player with neither the Hall of Fame playing resumé of Davenport or Navratilova, nor the coaching track record of Gullickson.
Of those players and others who recently have sought the help of former players, Isner arguably had the most raw material left to mine even as he turns 30 in two weeks.