Venus Williams upended defending champion Johanna Konta 5-7 6-1 6-2 on Monday to reach the Miami Open quarter-finals while a dominant Victoria Azarenka also advanced with a straightforward win over Agnieszka Radwanska. Three-times champion Williams stormed back from an early deficit to cruise past the British 11th seed, who needed several bouts of treatment on her lower back throughout a match that lasted two hours and 19 minutes. Perhaps more impressive was that Williams, who turns 38 in June, was able to look so in control despite playing a day after spending nearly three hours on the court for her third round clash against Dutchwoman Kiki Bertens.