Agnieszka Radwanska has admitted that she failed to take her chances during this morning's Australian Open last-16 defeat at the hands of Venus Williams.

The sixth seed came unstuck in a 6-3 2-6 6-1 loss at Melbourne Park to end the opening Grand Slam event of the year on a low.

Having comfortably won the second set Radwanska, was favourite to see out the match, although she was unable to capitalise on various openings to see the contest slip by.

"I think it was three kind of easy sets," she told reporters. "But I think the games were pretty tight. I think in important moments I didn't really take my chances. Slipped very quickly, especially the third set.

Asked if she took on an improved Williams today, Radwanska added: "Definitely. She was playing very well, very solid from the back, very good serve as well.

"You know, moving also very well. It was a little bit slower than during the day, different conditions, I guess. I prefer faster conditions against her. But obviously it was night session."

Madison Keys awaits Williams in the quarter-finals of the tournament.