As Novak Djokovic ascended to the pinnacle of tennis history, Reilly Opelka was watching from the sidelines, using Djokovic's success to plot his own return from injury, culminating in a stunning boilover victory at the Brisbane International.

Novak Djokovic was beaten 7-6 (6), 6-3 by big-serving Reilly Opelka in the Brisbane International quarterfinals.

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.

Reilly Opelka defeats Novak Djokovic in the Brisbane International, praising the Serbian as the greatest tennis player ever and highlighting his own strong performance.

Novak Djokovic will not play any further part in this year's Brisbane International as Reilly Opelka has sealed the biggest win yet of his return to the sport after having most of the last 18 months on the sidelines injured.

Novak Djokovic's hunt for a landmark 100th ATP title ended with a whimper following an unexpected 7-6(6) 6-3 defeat by big-serving American Reilly Opelka in the Brisbane International quarter-finals on Friday.

TOPSHOT - Winner Reilly Opelka of the United States (R) and Serbia's Novak Djokovic shake hands at ... [+] the net after their men's singles quarter-final match at the Brisbane International tennis tournament in Brisbane on January 3,