Serena Williams denied choking after falling victim to one of the greatest ever comebacks yesterday, saying she was powerless as Czech foe Karolina Pliskova just went crazy and stormed into the Australian Open semi-finals.

Serena had Pliskova on the rack serving at 5-1 in the third set but the seventh seed fended off four match points to bounce back 6-4, 4-6, 7-5 and end the American's latest bid for a record-equalling 24th Grand Slam. "She just played lights out on match point, literally hitting lines," Serena said. "[Pliskova] just went for it, just went crazy on match point. She just played unbelievable."