Reilly Opelka follows his bif win over Novak Djokovic at Brisbane International with a semifinal victory over Giovanni Mpetshi Perricard.

BRISBANE, Australia (AP) — Novak Djokovic was beaten 7-6 (6), 6-3 by big-serving Reilly Opelka in the Brisbane International quarterfinals on Friday. Opelka served 16 aces — including one to finish off each set — to earn one of the biggest wins of the American's career.

Djokovic is in search of his 25th Grand Slam title at the Australian Open, but fell short of the semifinals at his warm-up event.

Citing a back injury, American Reilly Opelka retired from the Brisbane International final down 1-4 to Jiri Lehecka.

Did anyone expect Novak Djokovic's comfortable victory over Reilly Opelka in Brisbane? Certainly not! However, the Serb was the massive favorite in the quarter-final. Still, Reilly stunned Novak 7-6, 6-3, securing a place in the semi-final!

Jiri Lehecka claimed the Brisbane International men's title after Reilly Opelka retired with an injury while trailing 4-1 in the opening set.

Czech Jiri Lehecka has won the Brisbane International after feelgood story Reilly Opelka retired with a back complaint when trailing 4-1 in the final.