The queen of all socialites wed a Mexican count, Felipe de Alba, on April 13 1983, with their union annulled a day later when it emerged marriage number seven had not yet been quite annulled.
Yet Isner and Mahut spent three days in cahoots at the All England Club, their head-spinning 2010 match breaking record after record, and it all began on June 22, 2010.
Ten years on, and although the longest tennis match in history eventually did end, it stands to be an eternal marker of ultra-endurance.
'IT'S A BASKETBALL SCORE'
Like Max von Sydow's knight facing down Death over a chess board, Mahut eventually bowed, Isner unrelenting in his pursuit of the kill.
They spent 11 hours and five minutes in action, ace after ace, mental and physical torment, but the match spanned a full 46 hours and 34 minutes of the human race's existence.
It started inconspicuously at 6.13pm on the first Tuesday of the Wimbledon fortnight and ended as a globally recognised phenomenon at 4.47pm on the Thursday.
Isner sent exceptional forehand and backhand winners fizzing past Mahut in successive points to take the win, sensational trolling from the American given both men were physically beat on their feet.
The match is quaintly recorded in Wimbledon's official compendium thus: J.R. Isner (USA) bt. N.P.A. Mahut (FRA) 6-4 3-6 6-7 (7-9) 7-6 (7-3) 70-68
That final-set score will forever have the air of a misprint, and Isner admitted to feeling "delirious" when play was suspended due to fading light on the Wednesday evening, the contest poised at 59-59 in the decider.
"It's a basketball score," Isner later told ESPN. "It always reminds me of that. I'll never forget these two numbers for as long as I live."
CALL THE COPS
You could watch The NeverEnding Story seven times in 11 hours and five minutes.
In the playing time that it took Isner to break Mahut's resistance, and his heart, you could watch Rafael Nadal's victory over Roger Federer in their epic 2008 Wimbledon final twice over, and be almost halfway through a third viewing.
You could watch The Lord of the Rings trilogy and leave yourself an hour and 47 minutes to wonder why you just did that.
Or you could watch all seven films in the Police Academy franchise and have a spare hour and four minutes to ruminate on whether Mahoney had a heart of gold or a hollow soul.
In 46 hours and 34 minutes, you could indulge your own Mission To Moscow fantasy and drive from the All England Club to the Russian capital, enjoying a couple of short overnight stays on the way.
EVEN THE SCOREBOARD COULDN'T BELIEVE IT
The truth is that barely anybody was engaged with Isner versus Mahut for its entirety. Different days mean different crowds at Wimbledon.
Isner, the 23rd seed, and qualifier Mahut were assigned a late-afternoon Tuesday slot on Court 18, one of Wimbledon's smaller show courts but a hidden gem, and it was only on the Wednesday, when the fifth-set score kept nudging up, that media-room interest began to whip up.
By tea time on the second day, it was the longest match in Wimbledon history, then the longest in all grand slams, going beyond the six hours and 33 minutes Fabrice Santoro needed to beat Arnaud Clement in their 2004 French Open tussle.
The big serving of both players was cooking up never-before-seen numbers.
The scoreboard stalled at 47-47, technology's own expression of disbelief. And yet tennis' Fischer versus Spassky continued, a trial of temperament as much as talent. There was no Cold War element, just the question of which man would crack as the pressure ramped up.
On day four, the UK's Queen Elizabeth II made a rare visit to Wimbledon, albeit not to spend the day on Court 18.
RECORD AFTER RECORD
Come Thursday's denouement, Isner and Mahut had contested the most games in a grand slam match, with 183 toppling the previous record of 112.
They had played the most games in a set, with their 138 eviscerating anything in the record books, and until the dramatic finale they had played 168 consecutive games without a break of serve. The run of holds began early in the second set.
The fifth set alone, lasting eight hours and 11 minutes, was longer than any entire match ever played in professional tennis.
Isner hit a mind-boggling 113 aces across the piece and Mahut made 103, a miracle of athletic achievement.
Serious aesthetes may have found little to love except the drama, but sometimes drama and shows of lung-busting human willpower outweigh finesse on the sporting field.
WHAT HAPPENED NEXT?
Isner bombed out a day later, thumped 6-0 6-3 6-2 by Thiemo de Bakker, with the American a victim of his own first-round excesses, but the match against Mahut will never be forgotten.
A plaque on the wall outside Court 18 marks what occurred there, Wimbledon's equivalent of a Hollywood star as passers-by queue to be photographed next to the permanent record.
The introduction of a fifth-set tie-break at 12-12 by Wimbledon in 2019 means there is no prospect of another 70-68 these days in SW19.
Freakishly, Isner and Mahut were drawn together again a year later in Wimbledon's first round. Second time around, Isner needed just two hours and three minutes to record a straight-sets win.
There's no plaque to mark where that happened – it was Court Three, for the record – nor is the rematch spoken of in the bars and restaurants of Wimbledon Village.
They still talk reverentially of the 2010 occasion though, with 'Isner-Mahut' shorthand for the spectacular sporting stamina that tennis had never known the like of before and surely will never again.
As Isner said, moments after walking off court: "I guess it's something Nic and I will share forever really."
