Australian Open fitness fears for Norrie after pulling out of Auckland

American top seed Ben Shelton had just powered past Spain's Roberto Carballes Baena 6-4, 6-3 when second seed Norrie withdrew from his quarter-final, handing Chile's Alejandro Tabilo a walkover.

Tournament director Nicolas Lamperin said Norrie had woken with a sore left wrist and "quickly found out that he wouldn't be able to play" during his warm-up.

"He was pretty devastated when he told us. We all know how much this tournament means to him," Lamperin added, with the first Grand Slam of the year starting on Sunday in Melbourne.

"He rushed straight away to the clinic to get a scan and obviously get some more clarity on what's wrong."

The 16th-ranked Shelton earlier reached his first semi-final since his maiden title win in Tokyo last year.

He broke Carballes Baena at 5-4 in the first set and at 4-3 in the second.

"He's definitely one of the faster players I've played against, running down balls, passing shots," said Shelton.

"But I felt like I brought out my best tennis in the big moments and I'm happy to be in a semi-final."

Shelton will play Taro Daniel in the semi-finals after the Japanese player beat French qualifier Alexandre Muller 6-4, 6-7(3), 6-3.

Arthur Fils, the sixth seed, will play Tabilo in the second semi-final with the French teenager's quarter-final against Germany's Daniel Altmaier also affected by injury.

After Fils took the first set and broke serve at the start of the second, Altmaier pulled out with an apparent back injury, leaving the 19-year-old as a 7-6(2), 1-0 winner.