Canadian teenager Victoria Mboko knocked Australian Open champion Elena Rybakina out of the Qatar Open quarter-finals, while world number two Iga Swiatek was beaten by the unseeded Maria Sakkari.
Mboko trailed 2-4 in the decider, but rallied to win the final four games in Doha to take a 7-5 4-6 6-4 win that moves her towards the top 10 in the WTA rankings for the first time.
The 19-year-old, who started the season ranked outside the top 300, has now beaten world number three Rybakina twice in their four encounters.
"I didn't really have that many expectations because she has a great record now, she just won the Australian Open.