The San Diego Open heads closer to its conclusion on Friday evening with the two semi-finals set to take place in California. Ahead of the action, our preview takes you through the two ties as the final will be set in this WTA 500.

The first one sees Barbora Krejcikova firmly on the comeback trail, face off against Danielle Collins. While the second one is technically two outsiders as Sofia Kenin faces Emma Navarro.

The first semi-final sees Barbora Krejcikova who is the fourth seed this week face off against Danielle Collins. The former sealed victory over Beatriz Haddad Maia early on Friday morning 6-4, 6-3.

This after seeing off Anhelina Kalinina. Since winning in Dubai, Krejcikova has struggled with injuries and form as she has not got back to the form that she showed in becoming a Grand Slam champion in particular.

But will face a Grand Slam finalist next in Danielle Collins. The former Australian Open finalist took down Caroline Garcia with ease 6-2, 6-3 ending her chances of a redemption run after also struggling recently and also defeated Jelena Ostapenko the round before.

A player who at her best can produce a run like in Australia or even more recently her run in Montreal, she is bound to be the favourite if she can get through this clash. It is also a Head to Head never played.

While in the second semi-final, Sofia Kenin who emerged from the section initially featuring Ons Jabeur saw off Anastasia Potapova 6-2, 6-3. She faces the surprise package left in the draw in 22-year-old Emma Navarro who reached a semi-final earlier on this season in Bad Homburg. She took down Maria Sakkari in a disheartening loss again for the Greek.

A player with a career high now of World No.53, she is seemingly playing some of her best tennis and has a good chance to make a maiden WTA Final.