I am not sure anyone can overstate what Muster did to come back from his injuries in early 1989.  An automobile accident in Miami nearly cost Muster his life.  In 1989, Muster reached the Australian Open semifinal round losing to Ivan Lendl and had reached the championship round at Masters Miami hours before being injured by a car.  Muster had a wonderful 1990 season winning in Rome and reaching the semifinal round at Roland Garros.  Still, had Muster’s knee not been smashed would his maniacal work ethic have led him to also being a big threat on hard courts as his 1989 results pointed toward.  Muster did reach #1 in early 1996 due to winning 11 titles on clay, 1 title on carpet, and being runner-up at 1 event on clay and 1 event on carpet in 1995.  In 1997, Muster reached the semifinal round at the Australian Open, claimed the Masters Miami title in what had to be an emotional victory, and finished as a runner-up in Cincinnati.  Muster’s best year on hard courts also saw him beaten at Roland Garros by a young Gustavo Kuerten on the clay he had dominated 2 years earlier.

Lendl and Muster did play an exhibition when Muster’s injuries had healed enough to allow his return to tennis