Venus Williams has booked a place in the semi-finals of the Qatar Open with a 6-4 1-6 6-3 victory over Agnieszka Radwanska in Doha.

It was a poor start for Radwanska as she was broken on her opening serve and later relinquished a break point.

Williams was able to maintain her advantage and took a one-set lead, but she suffered a wobble at the start of the second set by going a break down.

The American seventh seed managed to break back instantly, but Radwanska found her feet and battled to a further double break to draw level on sets.

Williams seemed to be in control again as she secured a crucial double break in the third set, but her Polish opponent refused to give up as she broke back.

However, it wasn't long before Williams wrapped up the contest on her serve.