On Thursday at the Mutua Madrid Open, sixth seed Andrey Rublev struck 32 winners to just 10 unforced errors. It still wasn't enough to get him across the finish line.

John Isner prevailed, 7-6 (4), 3-6, 7-6 (4), to clinch the third-round clash in two hours and five minutes. The American also posted a clean sheet, highlighted by 29 aces, but it was in the decisive tie-break where he stepped up most against an equally locked-in opponent.

"I haven't had many matches. But to beat a guy like that, maybe being a little bit undercooked, is a very special moment for me," Isner told press afterwards. "I'm actually pretty surprised right now to be in the quarterfinals."

Out of the seven points Isner took, six ended with a winner (including three aces). Rublev didn't go away quietly, either. Here's a rundown of each unreturned shot from the crucial juncture of the match.

Isner serving at 0-1: ace out wide.

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Madrid in GIFs: Isner's clutch tie-break effort outclasses Rublev

Isner serving at 1-1: finishes with inside-in forehand.

Madrid in GIFs: Isner's clutch tie-break effort outclasses Rublev

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Rublev serving at 1-2: finishes with backhand down the line.

Madrid in GIFs: Isner's clutch tie-break effort outclasses Rublev

Isner serving at 2-3: finishes with backhand crosscourt volley.

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Madrid in GIFs: Isner's clutch tie-break effort outclasses Rublev

Rublev serving at 3-4: Isner gets the mini break with inside-in forehand return.

Madrid in GIFs: Isner's clutch tie-break effort outclasses Rublev

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Rublev serving at 3-5: finishes with forehand down the line.

Madrid in GIFs: Isner's clutch tie-break effort outclasses Rublev

Isner serving at 5-4: ace out wide.

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Madrid in GIFs: Isner's clutch tie-break effort outclasses Rublev

Isner serving at 6-4: ace up the T.

Madrid in GIFs: Isner's clutch tie-break effort outclasses Rublev

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The victory marked Isner's second consecutive encounter decided by a final set tie-break, having edged home favorite Roberto Bautista Agut in the second round. The 36-year-old came into the ATP Masters 1000 event ranked No. 39, and needs to win his quarterfinal match Friday to ensure the U.S. isn't without a Top 30 player for the first time in ATP history when the new rankings are published next week. (current No. 1-ranked American Taylor Fritz will not maintain his spot at No. 30)

Awaiting the former world No. 8 is No. 3 seed Dominic Thiem, a 7-6 (7), 6-4 winner over Alex de Minaur. The Austrian holds a 2-1 lead in his head-to-head series with Isner, though the two haven't met since Thiem won a contest at the inaugural edition of Laver Cup in 2017.

"I think Dominic is 100% ready to go. He hasn't had that many matches, but he has two matches under his belt here," said Isner. "Any player will tell you once you get some wins, that snowball effect happens. You start to get some momentum. I think he's experiencing that right now."

Madrid in GIFs: Isner's clutch tie-break effort outclasses Rublev

Madrid in GIFs: Isner's clutch tie-break effort outclasses Rublev