Donald Young

No quarter a given: Djokovic, Thiem out; Chung, Sandgren in

Even by Australian Open standards, back-to-back shockers have resulted in a most unexpected quarterfinal.

The season-opening Grand Slam has a tendency to be unpredictable, but losing six-time champion Novak Djokovic and fifth-ranked Dominic Thiem within a few hours on Monday leaves Hyeon Chung and Tennys Sandgren playing for a spot in the semifinals.

The 58th-ranked Chung relentlessly attacked a clearly injured Djokovic in a 7-6 (4), 7-5, 7-6 (3) fourth-round victory, becoming the first South Korean to reach the last eight at a Grand Slam.

Then there's Tennys. The 26-year-old from Tennessee had never won a Grand Slam match or beaten a top-10 player until last week....