Alexander Zverev said he was "annoyed" at having to justify being world number one as he lost his opening match at the Paris Masters, while 24-time Grand Slam champion Novak Djokovic also fell in a Wednesday full of upsets.
Carlos Alcaraz avoided a similar fate, however, as the seven-time major winner beat Alex Michelsen 7-6 (7/4), 6-3 to advance to the last 16.
Long seen as tennis' nearly-man, 29-year-old Zverev broke his major duck this year by winning the French and US Opens, which propelled him to the top of the ATP rankings for the first time in his career this month.
But his reign as world number one got off to a disappointing start as 24th-ranked Lorenzo Musetti eased to a 7-6 (7/5), 6-2 win over the German to reach the third round.
Statement MADE by Musetti! 💪 @Lorenzo1Musetti puts in a stellar performance to prevail 7-6(5), 6-2 @RolexPMasters | #RolexParisMasters https://t.co/ZCg3sbnubT
— ATP Tour (@atptour) November 4, 2026
"Stress, I don't know if stress. I was a bit annoyed, to be honest," Zverev told reporters.
"I feel like I'm the only world number one in tennis history that has to explain why it's okay for me to be world number one, which I find quite difficult, because I think I deserve to be where I am, even though I lost today."
After being in a dominant position in the first-set tie-break, Zverev accumulated errors to lose five consecutive points and then six of the following eight games to crash out at the first hurdle.
"I said even before playing with him that today was going to be the best challenge and the toughest challenge that this sport can give me. So I'm really happy that I took my chances today," Italian former world number five Musetti said.
'DIFFICULT DAY FOR TOP GUYS'
Djokovic saw his hopes of winning an eighth Paris Masters title and qualifying for the ATP Finals disappear as he went out 2-6, 6-3, 6-3 to world number 83 Rinky Hijikata.
Green and GOLDEN performance 🇦🇺👏 It's a day @rinky_23 will never forget! @RolexPMasters | #RolexParisMasters https://t.co/CD8Is3QjmB
— ATP Tour (@atptour) November 4, 2026
After sailing to the first set, the 39-year-old then found himself in a battle with the Australian qualifier.
Hijikata broke Djokovic in the eighth game of the second frame before serving out to force a decider.
The third set ground on until the Serb cracked twice in a row on serve to hand his 25-year-old opponent victory.
The loss effectively brought to an end Djokovic's season with the veteran telling reporters his plan for the coming weeks was "just rest".
The 2023 Australian Open doubles champion will play Tomas Martin Etcheverry for a berth in the quarter-finals, after the Argentine downed Australian eighth seed Alex de Minaur 7-6 (7/2), 6-3.
Former world number one Daniil Medvedev joined the top-seed exit list as the fifth-ranked Russian crashed out in straight sets to Peru's Ignacio Buse.
Second seed Alcaraz managed to buck the trend with victory over 35th-ranked American Michelsen.
Transfering captivating tennis from Vienna 👉 Paris 💥 6 wins in a row, 12 successive sets for @carlosalcaraz! @RolexPMasters | #RolexParisMasters https://t.co/MXLY307zWF
— ATP Tour (@atptour) November 4, 2026
"Really happy to get the win," Alcaraz said on-court.
"It's been a really difficult day for the top guys, but I just try not to think about it and I try to step out there, play my best and enjoy," he later told reporters, after avoiding a repeat of his own opening defeat in the French capital last year.
Both players exchanged breaks of serve midway through the first set as the opener rumbled towards a tie-break.
Michelsen raced into a 4-1 lead in the breaker before Alcaraz found his forehand and blitzed through the next six points to seize the lead.
After a tightly-contested second frame, Alcaraz got a crucial break ahead in the eighth game and then promptly served out to set up a third-round meeting with Matteo Berrettini.
Elsewhere, seventh seed Frances Tiafoe also fell in his opening match, going down 6-3, 1-6, 7-6 (11/9) to Quentin Halys.
The Frenchman's victory over the American was doubly good news for the host country as it meant Arthur Fils qualified for the ATP Finals.
The Frenchman's victory over the American was doubly good news for the host country as it meant Arthur Fils qualified for the ATP Finals.
The French world number seven is now assured of making his debut at the season-ending tournament, which runs November 15-22 in Turin.
With that weight off his shoulders the 22-year-old closed play for the day with a 6-3, 7-6 (7/4) win over Czech qualifier Tomas Machac.
Ben Shelton will headline the day session on Thursday as the third seed takes on home favourite Arthur Rinderknech for a spot in the last eight, before Alcaraz returns in the night session to face Matteo Berrettini.