Teenager Arthur Fils has dumped defending champion and fellow Frenchman Richard Gasquet out of the ASB Classic.
The 19-year-old won in straight sets in their first round match in Auckland.
Gasquet had come to Auckland with 956 consecutive weeks in the world's top 100 which is the longest active streak.
Fils, already ranked 35th in the world with an ATP title to his credit, was in a different league and playing a different game, led by an 81 percent first service stat for his first time on the sold-out centre court.
"It was a nice crowd. It was the first time I have played beside some people eating and drinking but it was pretty nice. It was a joy to play on centre-court," said Fils.
"Both of us lost a bit of control but I served pretty good and managed to break his serve two times and hold my own, so I am pretty happy with it."
Fils said he greatly respects fellow French stars Gasquet and Gael Monfils.
"Richard is a great champion who won here last year. I was a little nervous before the match but I was very happy to play him and I hope I will play many more time against him.
"Gael inspires me, and is one of the most entertaining persons I know. Everyone wants to watch him play. Yesterday I was watching his match - because I know something is going to happen. Now he is 60 on the Tour and I hope one day to play against him."
Fils said he has a simple approach, not reaching too far ahead, but winning as many matches as he can.
"I will try my best but there are very good players - Cameron Norrie, Ben Shelton, Felix Auger Aliassime - but I will try my best. Tomorrow I play Nuno Borgos so let's see. I am taking everything that I can.
"It is very nice to play on such a good court, enjoying myself playing against some of the greatest players in the world and doing my best.
"I do not have actual goals but if I can win everything then I will for sure. If I can I will do it. It is a tough sport and you lose some days."
Two-time winner at the ASB Classic, Roberto Bautista Agut was another champion who could not advance beyond the first round this time, losing to fellow Spaniard Roberto Carballes Baena in straight sets.
It was the first meeting of the two Spaniards with Carballes Baena ending Bautista Agut's 10- game winning streak at the ASB Tennis Arena.
Canada's Denis Shapovalov, once in the world's top 10 and now out of the top 100, had his return halted by Austrian Sebastian Ofner 6-4 6-2 in a surprisingly one-sided affair.
He is working back into the sport after a lengthy time on the sidelines with a knee injury.
New Zealand's Davis Cup rep Kiranpal Pannu came up just short in his push for a first tour-level win, going down to Australia's world No 45 Max Purcell 6-4 6-4.
The US-based Pannu, ranked 500 places behind Purcell, had his opportunities but the Australian took advantage of errors on two service games which spelled the difference.
"I was proud with how I played and not overawed like last year," said Pannu. "In the end there was two sloppy service games that was the difference. I had a real chance but he took advantage which is why he is top-50 in the world."
Pannu will remain in New Zealand to prepare for the upcoming Davis Cup tie before returning to the circuit, giving himself the next 12 months to work his way on to the ATP Tour.
The top four seeds have their first action on Wednesday, with top seed Ben Shelton (USA) up against Hungary's Fabian Marozsan, who accounted for Gail Monfils on Tuesday.
Last year's runner-up, Cameron Norrie takes on French qualifier Luca Van Assche in the evening match on centre-court; third seed Francisco Cerundolo (ARG) meets qualifier Alexandre Muller (FRA) while Felix Auger-Aliassime (CAN) plus Impressive German Daniel Altmaier.
There was no fairytale send-off for veteran New Zealand player Artem Sitak, who was given a wildcard to compete in what will be his final tournament as a professional, before taking up a coaching role in England.
He paired up with fellow national representative Rubin Statham in doubles, but they were beaten by Romain Arneodo (MON) and Sam Weissborn (AUT).