Third seed Alexander Zverev was sensationally dumped out of the Miami Open second round as Finnish 21-year-old Emil Ruusuvuori claimed his second top 10 win of his career.
Ruusuvuori bounced back after losing the first set, changing his tactics and overwhelming the German on Friday to set up a third-round meeting with Mikael Ymer.
Ninth seed Grigor Dimitrov also bowed out, going down to Briton Cameron Norrie, while eighth seed David Goffin lost to James Duckworth.
World number two and top seed Daniil Medvedev eased past Lu Yen-hsun, while 11th seed Felix Auger-Aliassime, Karen Khachanov and John Isner all progressed.
TURNAROUND STUNS THIRD SEED
Zverev may have won last week's Mexican Open and the opening set 6-1 against Ruusuvuori but the tables turned quickly as the Finn produced one of the best displays of his career to date.
The 83rd-ranked Finn moved regularly to the net and was aggressive in his approach, leaving Zverev rattled before winning 1-6 6-3 6-1 in a stunning momentum shift.
"I don't even know myself," Ruusuvuori said in his on-court interview when asked how he turned the match around.
"I wasn't feeling very comfortable in the first set and I was making a lot of unforced errors but slowly in the second I was starting to feel a bit better... Of course, it's one of the biggest wins in my career so it feels good."
He will next face Ymer, who knocked out 27th seed Nikoloz Basilashvili.
NINTH SEED BUNDLED OUT
Former world number three Dimitrov was ousted from the Miami Open on Friday, losing 7-5 7-5 to 56th-ranked Norrie.
The Bulgarian took an early break and served for the first set at 5-3 but Norrie showed his mettle to break back twice to take the opener.
Norrie sent down 10 aces and was strong on serve throughout, claiming a significant win for his burgeoning career.
"It's huge," Norrie said. "He's had a good start to the year. It was such a physical match at the start. He came out really fast and he set the tone at the beginning of the match. Massive one for me and I take a lot of confidence from it."
Norrie's win sets up a third-round meeting with American Taylor Fritz, who beat Marcos Giron 6-2 6-2.
DANIIL DOMINATES, GOFFIN SHOCK
Australian Open runner-up Medvedev made light work of Lu, winning 6-2 6-2 to book a third-round match with Australian 21-year-old Alexei Popyrin.
Medvedev won in less than an hour, hitting 24 winners and nine aces and making few errors in a clinical display.
Canadian 11th seed Auger-Aliassime proved too good for Pierre-Hugues Herbert 6-4 6-4, setting up a third-round meeting with 18th seed Isner, who got past qualifier Mackenzie McDonald.
Seventh seed Roberto Bautista Agut progressed by virtue of a walkover against Lloyd Harris, who had a wrist issue.
Eighth seed Goffin lost to world number 104 Duckworth 6-3 6-1 in a boilover.