SERENA WILLIAMS’S yells of “Come on!” crescendoed right along with the tension in a fourth-round US Open match last night that began as a rout and suddenly became riveting.

When she ripped a backhand winner to claim the third set’s opening game, Williams let out her loudest shout of the day, leaning forward and rocking both arms. This turned into a test and she passed it.

Williams reached the quarter-finals at Flushing Meadows for a 10th consecutive appearance — she wasn’t there last year because she gave birth to her daughter during the tournament — by picking her level up after a lull and using 18 aces to beat Kaia Kanepi of Estonia 6-0 4-6 6-3.

“It was a ‘Serena scream. I don’t try to do it. It just comes out, and it’s just emotions,” said Williams, a six-time US Open champion who finished with more than twice as many winners as Kanepi, 47-22.

“This is my job and this is what I do. This is how I earn a living. I’m going to do it the best I can,” she added. “Winning a big game and a very important game and a really tight game, I think it was just a relief.”

This match was filled with big hitting by both women, along with all manner of shifts in momentum and quality of play. In the 18-minute shut-out of the first set, Kanepi’s strokes were off and Williams’s were pretty much perfect as she grabbed 24 of 30 points.

But, after compiling 14 winners and only two unforced errors in that set, Williams began making mistakes, becoming less and less comfortable as Kanepi grew increasingly so. Kanepi is ranked only 44th, but she’s been a top-20 player in the past and has made it to Grand Slam quarter-finals a half-dozen times. That’s nothing compared to Williams’s 23 major titles, but it’s something. Plus it’s worth remembering that Kanepi eliminated No 1 Simona Halep on day 1 of this tournament.

In a blink, Williams had a match on her hands. Kanepi was matching Williams’s power with booming groundstrokes of her own. She was getting better reads on Williams’s serves and Williams began making more and more mistakes.

When Williams shanked a backhand return of a 103mph serve, the match was a little more than an hour old and it was all tied at a set apiece. That was the first set she had lost against Kanepi of the 10 they’d played to that point and the first set Williams had lost at the 2018 US Open in a run that included a 6-1 6-2 victory over her older sister Venus in the third round Friday night.

After that scream-inspiring hold to begin the final set, Williams broke right away to lead 2-0. She then faced a break point, but Kanepi wasted that chance by sending a backhand wide. From there, Williams smacked an ace at 118mph, followed by a service winner at 113mph to go up 3-0, and that essentially was that.

Kanepi’s take on Wiliams’s serve? “Unreturnable,” she called it.

Next for the 36-year-old comes a quarter-final against 2016 runner-up Karolina Pliskova, who beat Williams in the US Open semi-finals that year.