Melbourne, Australia (SportsNetwork.com) - Madison Keys continued her stunning run through the Australian Open with a quarterfinal victory over fellow American Venus Williams on Wednesday.

Keys, who never before appeared past the third round of a Grand Slam, battled through a thigh injury and overcame 45 unforced errors to pull out a 6-3, 4-6, 6-4 victory over her older countrymate.

The 19-year-old Keys cruised in a 29-minute first set but struggled with a thigh injury in the second. Williams took that set with an ace, and the third fittingly went back-and-forth.

Williams, who was seeded 18th and came into the match 9-0 on the year, twice went up a break, and Keys promptly answered with one of her own.

Up 5-4 on Williams' serve, Keys closed things out with four consecutive points at love. On match point, she caught Williams on her heels with a deep forehand that was returned into the net.

The outcome ruined any chance at an all-Williams semifinal, as Serena Williams is set to face Dominika Cibulkova in Wednesday's other match.

Venus Williams, at 34-year-old, was trying to win her eighth major.