Daniil Medvedev was the biggest casualty on a day of upsets at the Indian Wells tournament on Monday.
The US Open champion lost 6-4, 3-6, 1-6 to France’s Gael Monfils. The defeat brought an end to his three-week reign as World No 1.
This was 35-year-old Monfils’ his first win over a World No 1 since 2009. He sealed victory in two hours and six minutes after converting his sixth match point.
“When I play my best tennis, my good tennis, it’s really tough to beat me,” said the Russian. “But that’s the toughest part of tennis is to reproduce it time after time.”
The shocks continued in the evening session as Greek fifth seed Stefanos Tsitsipas tumbled out to 21-year-old American Jenson Brooksby.
Brooksby, ranked 43rd in the world, advanced to the last 16 with a 1-6, 6-3, 6-2 win.
Two-time Grand Slam champions Petra Kvitova and Victoria Azarenka were also sent packing.
Maria Sakkari defeated Kvitova 6-3, 6-0 to book a place in the fourth round.
After the tearful exit of four-time Grand Slam champion Naomi Osaka on Saturday, there was another emotional flashpoint as Azarenka succumbed to Kazakh Elena Rybakina 6-3, 6-4.
Rybakina’s victory was overshadowed by a bizarre incident which came while Azarenka prepared to serve while trailing 6-3, 2-2.
Play was held up for several minutes as the 32-year-old two-time Australian Open champion dissolved into floods of tears, waving away intervention from the chair umpire saying “I’m sorry, I’m really sorry.”
Rybakina described the incident as a “very strange situation”.
“I just hope everything is good with Vika because I don’t know what happened,” she said. “Hope everything is okay.”