The double faults first became a problem as Popyrin – a Roland-Garros junior champion in 2017 who was born in Sydney to Russian parents – tried to serve out the second set and level a riveting slugfest between two friendly rivals.
The 25-year-old had weathered the storm coming from the other end of the court and held triple set point to level their round-of-16 stoush at a set apiece.
That is where it all unravelled for Popyrin, weeks separated from a career-best Masters 1000 triumph in Montreal and two days after dethroning defending champion Novak Djokovic.
Back-to-back errors of varying difficulty followed, before Tiafoe nailed a down-the-line backhand return winner to enliven an Arthur Ashe Stadium crowd baying for their countryman.
Two points later, the Australian double-faulted off the net to change the course of both players’ fortnight. Fast-forward to the second-set tiebreak, and two more double faults helped put him in a two-set hole.
It was particularly galling, given Popyrin also held consecutive break points in the fourth game of the match, at a time his Dunlop axe was causing all sorts of wounds to Tiafoe.
They traded turns with the momentum, but the man known as “Big Foe” made them count more often, leaving Popyrin with the titanic challenge of chasing the United States hero down in front of his home crowd.
The third set was surprisingly uncompetitive from Tiafoe, who twice dropped serve and barely escaped another time in between, giving Popyrin hope of doing the unthinkable.
That set the stage for an absorbing fourth set, where both players again had their chances.
Tiafoe had lost 15 of the previous 20 points by the time he collapsed to 0-30 in the third game of the set – and Popyrin was snarling for more. Popyrin barely missed a scorching backhand return on the ensuing point, but the next one summed up his night.
Having worked his way on top in the point, Popyrin opted for an ill-advised drop shot that was not only the wrong choice but was poorly executed, giving Tiafoe ample time to chase it down and put a forehand away.
The American held two points later, shutting the door on another Popyrin opportunity.
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Serving at 2-3, Popyrin double-faulted for 0-30, then did so again on the second break point he faced in the game to fall behind for good despite his last-gasp attempts almost resuscitating his comeback.
Popyrin finished with 24 aces and 55 winners to Tiafoe’s 14 and 44, but also nine double faults to his conqueror’s one. In a match of small margins, that was one of the key differences.
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