Indian Wells, CA, United States, 10 March 2019 | AAP /

Alex de Minaur has been upset by world No.217 Marcos Giron in the second round of the ATP Masters 1000 event at Indian Wells.

De Minaur, seeded No.23, scorched through the first set but American qualifier Giron swung the momentum his way against the 23-seeded Australian to prevail 1-6 6-4 6-2 and claim just the third tour-level win of his career.

De Minaur was one of four Australians to fall on Saturday, in a vastly different day for the green-and-gold to 24 hours earlier, when all four Aussies won their matches.

Late on Saturday night, Jordan Thompson fell to seventh seed Dominic Thiem 6-4 7-5, but not before giving the Austrian a big fight at Stadium 2.

Down a set and an early break, Thompson gritted out a hold in a third game spanning 13 deuces and 20 minutes, and later broke Thiem in the eighth game to level at 4-4.

Thiem broke Thompson to earn a chance to serve for the match leading 6-5, and although Thompson scored a break-back point to send the set to a tiebreak, Thiem eventually prevailed in one hour and 53 minutes.

Earlier, No.31 seed Nick Kyrgios also exited the tournament, falling 6-4 6-4 to German veteran Philipp Kohlschreiber.

Kyrgios entered the tournament after winning the ATP title in Acapulco and had he beaten Kohlschreiber, would have faced a likely third-round meeting with world No.1 Novak Djokovic.

Kyrgios went ahead 0-40 in the fifth game of the first set and held a total of four break points, yet Kohlschreiber escaped, and then broke Kyrgios in the seventh game, and then again in the fifth game of the second set, to wrap up victory in one hour and 14 minutes.

In the women’s event, Ajla Tomljanovic was beaten in the second round by ninth-seeded Aryna Sabalenka.

World No.44 Tomljanovic fought back from a set down to take the match to a deciding set but Belarusian Sabalenka proved too strong to close out the encounter 6-3 4-6 6-0.

On Sunday, Ash Barty will feature in a night match on Stadium 1 against American Jennifer Brady, while Daria Gavrilova and Alexei Popyrin will grace Stadium 2 against Elina Svitolina and John Isner respectively.

Alex Bolt takes on Guido Pella on Stadium 9, and Nick Kyrgios will take part in doubles action alongside Taylor Fritz.