Top seed Dominic Thiem was knocked out of the Rio Open by Italian qualifier Gianluca Mager in the completion of a rain delayed quarter-final match on Saturday.

Mager, 25, reached his first ATP Tour semi-final by winning 7-6 (7-4) 7-5 after leading 2-1 in the second set when play was halted on Friday.

The Italian held his opening three service games to serve for the match at 5-4.

But after dropping serve to Austrian Thiem, Mager landed back-to-back winners and on his first match point, fired an ace out wide to complete the win.

Mager will play Hungary’s Attila Balazs in a semi-final later on Saturday after he outlasted Spanish qualifier Pedro Martinez 2-6 6-4 6-2.

World No.4 Thiem was playing in his first tournament since reaching the Australian Open final last month.