Ana Ivanovic has booked her place in the semi-finals of the Madrid Open with a comfortable straight-sets victory over Germany's Angelique Kerber.

Ivanovic took control of the match in the early stages, breaking Kerber in her first service game to race into a 3-0 lead.

Kerber came back with a break of her own to make it 3-2, but Ivanovic held her serve to take the set 6-3.

Ivanovic then dominated the second set, breaking on three occasions and holding her serve well to establish a 5-0 advantage.

Despite losing the sixth game, 16th seed Ivanovic broke once more to wrap up the second set 6-1 and seal her place in the last four.

Ivanovic will face Maria Sharapova in the semi-finals.