His roar at match point said it all.
In doing so the reigning champion picked up an impressive accolade.
After the first stage, the likes of Rafael Nadal and Roger Federer have plenty to do to reach the ATP Finals last four.
“Obviously when I play this aggressive tennis, when I play this way, I have now beaten all three guys on this court, big three, so it shows that I can play very well and beat the top players,” said Zverev, closing out victory without facing a break point, who toppled Novak Djokovic and Roger Federer in the O2 Arena last November.
There were question marks over Nadal’s involvement due to an abdominal strain picked up in Paris, but Zverev was alert to the Spaniard’s short ball, delivering a clinical performance for a maiden win over the 19-time Grand Slam champion.
“I’m super happy, obviously. It was a great night for me, especially, me struggling the whole year. I want to use the opportunity as much as I can and do the best as I can.”
Roland-Garros champion Nadal was gracious in defeat, refusing to make excuses.
"I did not feel pain in the abdominal at all... we can find reasons or excuses, but at the end of the day, what all really matters is I need to play much better in two days after tomorrow."@RafaelNadal | #NittoATPFinals pic.twitter.com/1eyKM3RSXH— ATP Tour (@atptour) November 11, 2019
“I did not feel pain in the abdominal at all. No, just Sascha, well played, and me, bad played, honestly,” reflected Nadal, believing he missed his edge on court.
“I stay positive. I stay competitive, something that today I was not. That's the thing that I am more disappointed, because knowing that I will not be at my 100 percent in terms of feelings, in terms of movement, in terms of confidence or hitting the ball, I needed my best competitive spirit this afternoon, and I was not there in that way.”
In an additional concern for Nadal, on Monday Novak Djokovic sent out an illuminating signal of intent to dismiss debutant Matteo Berrettini 6-2, 6-1 in just 63 minutes.
The Serbian has won four of his five ATP Finals trophies at the O2 Arena (2012-15) and is seemingly extra motivated to reclaim the title, alongside his spot at the top of the rankings.
Djokovic must reach the final to have a chance of usurping Nadal and soared to victory looking as fresh and fiercely determined as the start of 2019.
“I kind of push myself and try to create even more energy for these last couple of tournaments,” declared the Rolex Paris Masters champion.
“And also, knowing that I have done so well throughout my career on indoor courts, especially Bercy and London back to back, kind of every year gives me more motivation and confidence coming into these tournaments.”
Extra confidence coursing through Djokovic is an ominous sign for the field, with Dominic Thiem next up on Tuesday evening.
The Austrian navigated past Djokovic en route to the Roland-Garros final and is in the groove once again.
A 7-5, 7-5 scoreline over Federer doesn’t quite indicate how well Thiem played, rushing the six-time champion and keeping the Swiss off his strike zone.
“To beat him, everything has to fit together. Today I think was the case again. I played very well,” stated 26-year-old Thiem, picking up his third successive victory against Federer in 2019.
“The system is pretty brutal, I would say, because I had amazing victory today.
“I'm feeling great. I'm feeling now that I have a good chance to reach the semis, but if I lose on Tuesday, for example, everything is completely open again, and I have to worry about everything on the next match on Thursday.”
For Federer, without an ATP Finals trophy held aloft since 2011, the 38-year-old will have to replicate his 2018 escape from the group stages after an opening match defeat.
“It's a normal tournament from here on forward. I’m not allowed to lose anymore,” said the 20-time Grand Slam winner, who takes on Berrettini next. “That's how it is every week of the year for the past 20 years, so from that standpoint, there is nothing new.”
Gregarious Greek Stefanos Tsitsipas thrived on ATP Finals debut to dispatch Daniil Medvedev 7-6(5), 6-4.
Tsitsipas covered the court with athletic ease, canvassing the net to succeed in 13 of 17 attempts, to overturn the 0-5 head-to-head facing the US Open finalist.
“It’s one of the most important victories in my career so far. I gave myself a big boost today, kept believing, kept fighting. It’s such a relief,” revealed Tsitsipas. “It’s not easy coming in knowing you’ve lost five times before, but I made a deal with myself that I’ll keep trying until I get it. It doesn’t matter if it’s 10, 20 times.”
French duo Pierre-Hugues Herbert and Nicolas Mahut built on the momentum from lifting the Rolex Paris Masters on home soil to take down top seeds Juan Sebastian Cabal and Robert Farah 6-3, 7-5 on Monday.
“Reaching the final here last year gave us great motivation,” said Herbert. “It was a high-level match from both sides and we knew we needed to be good against the No. 1 team. We’re so happy with the level we played. To come through this first match is something special for us.”