'What happened': Tennis world in disbelief over major upset

Camila Osorio (pictured right) celebrating in tears after defeating Elina Svitolina.
Camila Osorio (pictured right) pulled off the biggest win of her career defeating No.1 seed Elina Svitolina. (Images: @WTAtour)

No.1 seed Elina Svitolina has been shocked after crashing out of the WTA Tour's Tenerife Ladies Open in the first round.

The World No.6 was taking on 19-year-old Camila Osorio in the first round when bad light interrupted play.

'NIGHTMARE': Australian Open facing staggering player revolt

'SOMETHING WRONG': Tennis champ's swipe at Emma Raducanu

'COUNTING DOWN': Tennis fans erupt over Novak Djokovic news

The Ukraine world No.6 led by a set against Osorio, overnight, and when play resumed on Wednesday took a 2-0 advantage to appear on course for a routine win.

However, the World No.63 produced some sublime tennis after she rattled off five games in a row on her way to forcing a deciding set.

The Colombian then won the final four game of the encounter to seal a comeback 5-7, 6-3, 6-2 victory.

Fans were stunned to see the World No.6 fall in the first round of the tournament.

Osorio records biggest career win

The 19-year-old had not got past the opening round in five of her past six tournaments but proved too good for Svitolina.

The 63rd-ranked Osorio will play Egypt's World No.64 Mayar Sherif for a quarter-final spot.

Already through to the last eight are a trio of unseeded players - after Svitolina's defeat meant six of the eight seeded players were bundled out in the opening round.

Ann Li beat Varvara Gracheva 6-4, 6-2 while Anna Karolina Schmiedlova defeated Jaqueline Cristian 6-2, 7-5.

Alize Cornet is through after her match against Xinyu Wang ended with the Chinese having to retire injured in the tird set with the Frenchwoman ahead 4-1.

The match between Donna Vekic and Romania's Irina-Camelia Begu was suspended at 6-4, 1-1 in favour of the Croatian.

with AAP

Click here to sign up to our newsletter for all the latest and breaking stories from Australia and around the world.