Daniil Medvedev lost his world number one ranking after a stunning 4-6, 6-3, 6-1 loss to Gael Monfils in the third round of Indian Wells on Monday, while fifth seed Stefanos Tsitsipas was eliminated by American Jenson Brooksby.
Monfils let out a roar as he secured the upset on the sixth match point in front of an adoring California crowd with a backhand winner to set up a meeting with Spanish teenager Carlos Alcaraz in the fourth round.
"I'm quite happy right now - I'm in my zone," Monfils said. "I moved quite good and then I changed the speed quite a lot."
The Frenchman handed Medvedev the break in the ninth game of the first set with a pair of double faults and two forehand errors, as the reigning U.S. Open champion dropped just four points on his serve in the opener.
But Medvedev lost the momentum in the second set, unable to convert on five of six break point opportunities.
Monfils broke him in the fourth game with a backhand winner and again in the eighth with a fiery forehand.
Overcoming obvious exhaustion, Monfils won the first four games of the final set as Medvedev was unable to set up a single break point opportunity.
It was the first time in 13 years that the 35-year-old Monfils beat the number-one ranked player in the world.
Twenty-times Grand Slam winner Novak Djokovic will return to the top of the world rankings when they are updated next Monday.
Later on Monday, local hope Jenson Brooksby fought back from a set down to secure a shock win over world number five Stefanos Tsitsipas 1-6, 6-3, 6-2.
Tsitsipas got off to a flying start, breaking twice to claim the opening set, but Brooksby stormed back into the contest in the second set, winning the first three games to take a 3-0 lead, which he held onto to force a decider.
Brooksby carried his momentum into the final set, breaking twice in quick succession to go 4-0 up, before he served out to eliminate the 23-year-old Greek.
"I felt really good going into the match. I was hitting well, I thought I prepared well but yeah, I just got a little tight," 43rd-ranked Brooksby said.
"I think I got a little bit in my own head (in the first set), but it's a whole match. I breathed a little bit, I calmed down and I got myself to turn things around."
Tsitsipas is the second top-10 player to have fallen at the hands of a young American in the tournament, with world number three Alexander Zverev crashing out after a 6-2, 4-6,7-6(2) loss to Tommy Paul on Sunday.
Spaniard Rafael Nadal sent Daniel Evans packing with a routine 7-5, 6-3 win to extend his unbeaten streak in 2022 to 17-0 after winning a men's record-breaking 21st Grand Slam title at the Australian Open.
Down an early break, Nadal levelled it in the eighth game and again broke Evans to close out the first set and seize the momentum.
He dropped just two first-serve points in the second set, breaking his opponent early and wrapping up his 400th Masters match win with a forehand winner before thrusting his hands in the air to cheers from the crowd.
He reaches the fourth round after staging a breath-taking, three-set comeback on Saturday against American Sebastian Korda and said after the match he was pleased to wrap up Monday's affair in a tidier fashion.
"Happy to be able to keep going in the tournament," Nadal said. "I think after a few games I have been playing better and better."
Nadal will next face American Reilly Opelka, who beat 13th seed Denis Shapovalov 6-7(4), 6-4, 6-4.
Elsewhere on the men's side, Alcaraz beat fellow Spaniard Roberto Bautista Agut 6-2, 6-0.
Sakkari steamrolls Kvitova in Indian Wells third round, Rybakina beats Azarenka
Greece's Maria Sakkari fired off five aces to make light work of Czech Petra Kvitova 6-3, 6-0 in the third round of Indian Wells on Monday.
The world number six won all of her first-serve points in the first set and dropped just one in the second, as Kvitova struggled with her serve, producing five double-faults across the 66-minute affair in California.
Two-time Wimbledon winner Kvitova ceded break point in the eighth game of the first set and never regained her composure, as Sakkari fended off two breaks to close out the frame and ran away with the match in the second set.
"It was a little bit tough for me to get used to her serve," said Sakkari, who reached the semi-final at Roland-Garros and the US Open last year.
"Once I broke her, I just felt like that's was the right way to return her serve and I was just very solid from the back of the court."
It was the second time that Sakkari has reached the round of 16 at tennis' unofficial "fifth major," after she reached the fourth round in 2018.
Later in the day's action, two-time winner and 13th seed Victoria Azarenka fell to Kazakhstan's Elena Rybakina 6-3, 6-4 after a malfunctioning serve saw her produce eight double faults.
An in-form Rybakina produced a pristine first set, launching four aces without dropping a single first-serve point to claim the early momentum.
With her right shoulder heavily taped and a sleeve placed on her right arm, two-time Australian Open champion Azarenka grimaced, crouched down on the court and wept after a double fault in the fifth game of the second set. That prompted the chair umpire to approach Azarenka to ask if she needed medical attention.
Azarenka, who lost in the final last year to Spain's Paula Badosa, apologized and continued but Rybakina converted the critical break point in the seventh game of the second set.
Elsewhere on the women's side, Czech Marketa Vondrousova knocked out Estonian fourth seed Anett Kontaveit 3-7, 7-5, 7-6(5).
