Certain events pale sport into insignificance and John Isners defeat to Marin Cilic was secondary to the tragic circumstances that preceded the contest.
The big-serving American learnt of the death of his former housemate Kyle Morgan, aged just 35, shortly after his defeat to Novak Djokovic on Monday night but returned to the O2 Arena on Wednesday evening to take on Cilic.
A visibly, and understandably, emotional Isner faced the media after the match and was close to tears as he discussed the impact his friend had on his life.
Yeah, I mean, when I left college, I worked out exclusively with Kyle for probably seven years, he said. I mean, thats four, five times a week for seven years. We lived together, as well.
Certainly very close. Its devastating not just for me, but for a whole bunch of people. He was a fantastic guy.
Found out two nights ago after I lost to Novak. But, yeah, its difficult, very difficult. Got to go out there and play.
Though the American came up short on the night, his courageous display given the circumstances was heralded by his Croatian opponent, who admitted he was unaware of Isners situation.
I actually didnt know, he said after the 6-7 (2-7) 6-3 6-4 win. Im very, very, very sorry to hear that. I didnt know.
Definitely John played a great match and credit to him for staying focused and playing that well.
I felt that he was serving extremely well, especially in that first part of the match and I just upped my game a bit towards the end of the second set and the third set as well.
Isner cut a very different figure from the buoyant man on display at the pre-tournament media day less than a week ago, where he was jubilant at qualifying for the season-ending event for the first time in his career.
It may prove difficult for Isner to separate it from the loss of one his close friends, who he said in a lengthy Instagram post that the years they spent in the gym together allowed me to compete at the highest level, but he could still potentially find some joy by qualifying for the semi-finals.
Despite losing his opening two matches, Group Guga Kuerten remains finely poised and a straight sets win over Alexander Zverev combined with Djokovic bearing Cilic would see him through.
Yeah, its very weird, to think Ive lost twice but still have a shot, Isner added. I guess thats the advantage of having a guy like Novak in your group.
I guess I have an objective, for sure. Well see if I can do it. Its going to be very tough, no doubt. Ill try on Friday. I play during the day, which is nice, not playing another night match. But well see.
Djokovic is the only player to have booked his spot in the semi-finals, with the rest of the field hoping to book their places in Thursday and Fridays matches.