Ash Barty had a straight-sets victory 6-3 6-2 over Kristina Mladenovic to continue her impressive run, having now won seven of her eight grass-court matches since the French Open.

She will face Su-Wei Hsieh, who advanced past an injured Magdalena Rybarikova.

Fellow Aussie Daria Gavrilova ensured her match went to the third set but fell short of joining Barty in the last 16. 

Gavrilova served for the match in the 12th game and held two match points, which turned out to be a battle that extended to five deuces.

Agnieszka Radwanska, who is a former world no.2 and Wimbledon finalist, was able to break serve and win the set to send the match into a decider, but that's when Gavrilova’s resistance crumbled.

Radwanska would win 5-7 7-6(4) 6-0 and now faces the in-form Petra Kvitova.

Stosur had crashed out in a thrilling matchup against Belgian Alison Van Uytvanck despite claiming the first set. 

A decisive tiebreak would be Stosur's undoing in the second set as she went down 7-5 6-7 3-6.