It was on yet another error by Shelton that the door reopened: the break was taken at 6-5. Van Assche immediately held serve and pocketed the set, 7-5, after 55 minutes. Van Assche made the most of it. After breaking his opponent's serve, he led 3-1, before going through a spell of doubt at the worst possible moment.
At 22 and ranked 47th on the ATP, Van Assche had never gone beyond the second round of a Masters 1000. He stood up to the finalist of the last US Open before a crowd firmly behind him, without turning that resistance into an upset.
The American then regained authority. More precise and more aggressive, he leaned on cannonball serves and a better-honed game, rid of the gifts of the first set.
Shelton wobbled, then ultimately made his ranking count. The Frenchman looked the world No. 4 in the eye before submitting to his rule.
In the first set, the American was able to rely on the power of his serve, but his forehand betrayed him: fourteen unforced errors opened breaches.
The Frenchman's unforced forehand errors then multiplied. Shelton, who had asked for no such favor, strung together four consecutive games and regained the upper hand.
The third set was an emotional roller coaster. Less clear-headed than at the start of the match and with his back to the wall, Van Assche tried to get back on level terms.
The script will no doubt leave the Frenchman with a few regrets, so close to unsettling the world No. 4.
He saved a match point, without managing to throw Shelton off on his final service game. The American closed it out 6-4.