Kerber downs Radwanska, makes semis

German tennis player Angelique Kerber beat Agnieszka Radwanska of Poland to reach the semi-finals of the Bank of the West Classic in Stanford on Friday night.

Radwanska and Kerber battled for over two hours, but as the match progressed the fifth seeded Kerber seems to be the stronger of the two and won the match in three sets against second seed Radwanska 4-6, 6-4, 6-4.

Kerber will next face eighth seeded Ukrainian Elina Svitolina, who came from a set down to beat Alison Riske of the US 4-6, 7-5, 6-1. 

Riske served for the match leading 6-4, 5-4 but Svitolina managed to break back to eventually win the second set, then went on to win the third comfortably.

The other semi-final match sees Czech fourth seed Karolina Pliskova up against American Varvara Lepchenko. 

Pliskova beat Ajla Tomljanovic of Croatia 6-2, 6-4, and Lepchenko came from a set down to beat Germany's Mona Barthel 6-7(3), 6-2, 6-3.