Angelique Kerber powers past Agnieszka Radwanska

Angelique Kerber has beaten world number four Agnieszka Radwanska in straight sets at the WTA Championships in Istanbul.

Radwanska has now been beaten by every player in the red group after the German won 6-2 6-2.

Kerber dominated throughout, pressuring the Radwanska serve and eventually wearing her opponent down for her first victory in the tournament.

Kerber will face Petra Kvitova in her final group match, with the winner likely to go through to the next round alongside Serena Williams.