Australia's two highest ranked players, Alex de Minaur and Nick Kyrgios, have been knocked out in the second round of the ATP Masters 1000 event at Indian Wells.

Coming off his spectacular title run in Acapulco, Kyrgios was an overwhelming favourite to advance from his meeting with Philipp Kohlschreiber.

But the German veteran proved too consistent as he broke the 31st seed once in each set to prevail 6-4 6-4 in one hour and 14 minutes.

A keenly-fought opening set went the way of Kohlschreiber after a slip by Kyrgios, who had kept his emotions in check, cost him a chance to break serve in the 10th game.

The incident resulted in Kyrgios trashing his racquet in frustration as he complained to his team about wearing "sample" shoes, which he changed out of at the end of the set and threw into the crowd.

Kohlschreiber broke to lead 3-2 in the second set at which point Kyrgios, already one of the fastest players on tour, proceeded to increase his pace of play with one service game taking just 38 seconds.

De Minaur, who like Kyrgios had a first-round bye, was upset by world No.217 Marcos Giron earlier on Saturday.

De Minaur 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.

Playing in just his fourth ATP tournament, Southern Californian Giron claimed just the third, and biggest, tour-level win of his career against the 20-year-old de Minaur.

Giron, 25, will be a heavy underdog when he faces Canadian 13th seed Milos Raonic, who pounded down 18 aces to send American Sam Querrey packing 7-6 (7-1) 6-4.

De Minaur wasn't the only seeded player to crash out in the second round as teenager Felix Auger-Aliassime stunned Greek ninth seed Stefanos Tsitsipas 6-4 6-2 to record his first top-10 scalp and Croatian veteran Ivo Karlovic ousted 11th-seeded countryman Borna Coric 6-4 7-6 (7-2).

The Canadian 18-year-old Auger-Aliassime, the youngest player in the top 100, overcame 20-year-old Tsitsipas, the youngest player in the 10, for the fourth time - after three encounters in the juniors.

World No.1 Novak Djokovic picked up steam during his second-round match against American Bjorn Fratangelo.

Djokovic sprinted over to the stands to shake hands with his idol, 14-times grand slam champion Pete Sampras, immediately after the 7-6 (7-5) 6-2 win.

France's revitalised Gael Monfils outlasted Argentina's Leonardo Mayer 6-4 3-6 6-3 to set up a match with Spaniard Albert Ramos Vinolas, who upset 15th-seeded Italian Marco Cecchinato 6-4 6-2.

Others to reach the round of 32 included Gilles Simon, Jan-Lennard Struff, Lazlo Djere and lucky loser Miomir Kecmanovic.