British number one Johanna Konta reached the Italian Open quarter-finals with a 6-2 6-4 win over Venus Williams - her second match of the day.

Konta, 27, came from a set down to beat world number eight Sloane Stephens before overcoming seven-time Grand Slam winner Williams, now ranked 50th.

Williams was hampered by injury and an assured Konta won in 72 minutes.

She will play Czech teenager Marketa Vondrousova or Russian Daria Kasatkina in the last eight in Rome.

Williams received a bye into the third round after sister Serena withdrew because of a knee injury.

Wiliams, 38, had won her past three meetings with Konta, including the 2017 Wimbledon semi-final.

Williams had her right knee strapped and, although she improved as the match wore on, Konta reached the first Premier clay-court quarter-final of her career.

World number one Naomi Osaka recorded consecutive 6-3 6-3 wins over Dominika Cibulkova and Mihaela Buzarnescu to set up a last-eight meeting with world number four Kiki Bertens.

Former French Open and Wimbledon champion Garbine Muguruza withdrew from her match against Victoria Azarenka with a thigh injury when 6-4 3-1 down.