Why Alexander Zverev hit out at AO organisers despite reaching the semi-finals at Melbourne Park; Tommy Paul

Paul acknowledged his frustration, but he was more concerned about winning only one point in two tie-breakers, putting Zverev on the road to victory.

“I mean, I was already down, like, 4-1 in the breaker. I think maybe double mini-break,” said the world No.11.

“I hit a serve, and it was a let, but the chair didn’t see it. I just didn’t know that there was no automatic – what’s it called – let machine here.

“It is what it is. That didn’t lose me the match or anything.”

It wasn’t the only moment at Melbourne Park this fortnight where the let protocols have left a player baffled.

New Zealand doubles player Erin Routliffe blew up during her third-round match on Margaret Court Arena on Monday, a match that Routliffe and Canadian Gabriela Dabrowski won in three sets.

Routliffe was incredulous after chair umpire Julie Kjendlie missed a let call decision as Routliffe, who was returning, struggled to put her racquet on the serve.

“I didn’t hear it,” Kjendlie said on court.

“I don’t have a machine. I’m calling it myself, and I didn’t hear it.”

But Routliffe couldn’t believe the circumstances. “Oh, my god,” exclaimed the 29-year-old.

“Oh my god, we have robots everywhere and we don’t have them for the net.”

Paul, who reached the semis in Melbourne two years ago, lamented his high error count in the four-set defeat. There were 56 unforced errors on Paul’s racquet, while Zverev committed 36.

“My unforced error count was just too high today,” said the 27-year-old Paul.

“I was looking at it. They had all the stats during the match up on the screen. I looked up and saw, like, 40-something unforced errors after, like, two sets or two and a half sets.

“You can’t have that when you’re playing guys who are No.2 in the world at slams.”

Zverev knew he’d dodged a bullet by getting past Paul, who was found wanting at vital moments.

“I feel like I stole both of those sets in a way because he was playing better than me, and he was serving for both of those sets,” said the German.

“In the tie-break I played quite well. He maybe missed a little bit more than he should have. Yeah, I’m happy that I won in four sets because this was a difficult one.”

It was a match where the margins were wafer-thin. It took close to three-and-a-half hours for the world No.2 to overcome Paul, even though Zverev raced to a 5-0 advantage in the fourth set before Paul rallied late.

The German summed up his fortunes immediately afterwards. Asked how he pulled out the win, Zverev said: “I don’t know, myself, to be honest.”

It’s not an understatement to say that Zverev has flown under the radar in reaching the pointy end at another major.

Tuesday’s contest against Paul on centre court was his first day match across 10 days at Melbourne Park. The 27-year-old has only dropped two sets en route to a showdown against either Novak Djokovic or Tommy Paul. Make no mistake, he won’t be hiding in the shadows in his next contest.

Zverev conceded he’s pleasantly surprised to be in the final four. Pre-tournament, last year’s Roland-Garros finalist admitted he wasn’t sure how he’d fare as he battled an injury and pulled out of the United Cup teams event ahead of Germany’s quarter-final.

“I was very uncertain coming into this tournament, I had an arm injury,” Zverev said on court.

“I didn’t have the preparation that I wanted.”

Zverev admitted that day timeslots aren’t his preference. “I absolutely love playing night matches here. I really do. I don’t know why. I feel the ball better on my racquet,” he said.

Earlier, Zverev was perplexed by falling feathers in the swirly conditions, including one moment when the umpire stopped play – ironically calling a let.

“I’ve never had that before that we stop a point because of a feather,” he said afterwards.

“That was new to me.

“Not sure it was a hindrance to anybody. It’s not like a hard object. Like, even if the tennis ball hits the feather, it doesn’t really change anything. It doesn’t change the trajectory of the ball, or the bounce of the ball, or anything like that.

“Maybe the umpire did the right call, and maybe not. I have no idea. But it was a bit frustrating because obviously Tommy then would get a first serve, and he won the point with that serve as well.

“I got a warning after that.”

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