On May 11 last year, American tennis player Steve Johnson was checking in for an early morning flight at Los Angeles International Airport. His mother, Michelle, rang, distraught. His father, Steve Sr, his mentor and confidant, had died suddenly in his sleep. He had suffered a heart attack.

Johnson, a genial Californian and one of the tour’s most popular, hard-working players, was “extremely close” to his dad, a professional tennis coach who taught his son from the age of two until Steve Jr’s all-conquering college career at the University of southern California.

After Johnson left university, his father went to most of his matches and proudly watched on as Steve Jr became the American No 1 and world No 21 two years ago (he is currently ranked No 44). When Johnson struggled to make the transition from college star to professional, and considered quitting, it was his father who insisted he kept going.

Not long after, Steve Jr won a men’s doubles Olympic bronze medal in Rio.

Johnson, 28, has endured a very tough year, and – unlike most sportspeople constrained by their macho surroundings – is open about the emotional toll it has taken.