World number three Casper Ruud's buildup for the Australian Open has suffered an unexpected blow after losing his first match at the Auckland Classic.

Top seed Ruud was stunned by 70th-ranked Laslo Djere of Serbia, who fought back from a set down to win their second-round contest 3-6, 6-3, 7-6 (7/3).

The Norwegian started strongly but was outplayed as the match wore on, struggling to handle the intensity of an opponent who admitted he surprised himself.

"It's a great feeling. It's been some time since my last win over a top-10 player, I've lost many in a row," Djere said.

"I'm happy I was able to turn it around against one of the best players at the moment.

"In the first set, not many things worked. I had a feeling I didn't have answers to his game, and then I tried some new things and it worked out. I'm a bit exhausted but also very happy."

Ruud, who lost his only other meeting with Djere four years ago, will need to dredge up some confidence ahead of the year's opening Grand Slam in Melbourne.

Having sat out a first-round bye in Auckland, his previous match was a straight-sets loss to Italian Matteo Berrettini at last week's United Cup.

Ruud's timing deserted him over the last two sets, with the 24-year-old struggling with a heavy Djere serve on the slick surface after rain forced the match indoors.

The result means seven of the eight seeded players have been eliminated ahead of the quarter-finals.

The exception is Cameron Norrie, although the British world number 12 had his hands full in beating 78th-ranked Czech opponent Jiri Lehecka 6-4, 6-7 (4/7), 6-3.

Patchy rain forced several stoppages and the players moved indoors early in the final set, which second seed Norrie said was a test of his composure.

"It's tough on the concentration," he said.

"We had to stop and start and you're constantly thinking 'am I going to slip on the lines'. It's not easy."

Argentina's two highest-ranked men's players Diego Schwartzman and Francisco Cerundolo both pulled out of the tournament, putting them in some doubt for the Australian Open.

The 25th-ranked Schwartzman retired from his match with a leg injury after losing the first set to American Jenson Brooksby.

Cerundolo didn't take the court for his match because of an apparent illness, citing "abdominal pain".