A tearful Steve Johnson said the recent death of his father left him an "emotional mess" as he won a dramatic match against Borna Coric at the French Open.
The American, 27, sank to his knees and cried on court after the four-set second-round win at Roland Garros.
Steve Johnson Sr, a tennis coach who introduced his son to the sport, died at the age of 58 earlier this month.
"I just miss my dad," the world number 26 told Tennis Channel.
"I wish he was following along - I know he is from upstairs - but it's just so emotional, it's hard to describe.