John Robert Isner (born April 26, 1985) is an American professional tennis player. He has been ranked as high as world No. 8 in singles and No. 19 in doubles by the Association of Tennis Professionals (ATP).

Considered one of the best servers ever to play on the ATP Tour, Isner achieved his career-high singles ranking in July 2018 by virtue of his maiden Masters 1000 crown at the 2018 Miami Open and a semifinal appearance at the 2018 Wimbledon Championships.

He has also twice reached the quarterfinals at the US Open in 2011 and 2018, the latter of which helped qualify him for an ATP Finals appearance later that year. At the 2010 Wimbledon Championships, he played the longest professional tennis match in history,

requiring five sets and 183 games to defeat Nicolas Mahut in a match which lasted 11 hours and 5 minutes, and was played over the course of three days.[3] Isner holds the record for hitting the ATP's fastest "official" serve ever and third-fastest on record in tennis at 157.2 mph or 253 km/h during his first-round 2016 Davis Cup match.

For those of us that watch tennis regularly we can expect an average three-set match to last around an hour and a half, 30-40 minutes or so per set. Of course, put a top seed against a debutant and it can all be over in a jiffy. 

Then again, when you have two players on a par with each other, we can expect it to go on somewhat longer, and if we’re talking about a major tournament like Wimbledon, then we could be taken into a fifth set and significantly longer viewing time.

That match spanned 11 hours and five minutes, with Isner, then number 10, eventually triumphing 6-4, 3-6, 6-7, 7-6, 70-68 in an astoundingly long final set.

The 665-minute victory was spread out over three days beginning on 22 June and concluding on 24 June, with play having to be stopped twice due to a lack of natural light. Big serves after big serves entertained and thrilled the various selections of onlookers who needed numerous refills of strawberries and cream.

Such was the unexpected nature of the match length that the electronic scoreboard stopped functioning at 47-47 in the fifth set as, fairly understandably, it had not been programmed to keep scores beyond that point.

And this was a big reason for the record contest between was that both players were better at serving than returning, and both were serving particularly well during the nearly interminable fifth set.