Maria Sakkari progresses in San Diego as Sofia Kenin reaches first quarter-final since January

Third seed Maria Sakkari progressed to the last eight of the San Diego Open on Wednesday, while Sofia Kenin reached her first quarter-final since January.

Sakkari was leading 6-3 2-2 against Camila Osorio when the Colombian was forced to retire.

The 28-year-old claimed the only break of the match in the opening set and saved the one break point she faced, while winning 73% of first serve points.

She will be joined in the last eight by Kenin, who overcame fellow American Katie Volynets in a three-set thriller.

Things looked bleak for the former Australian Open champion when she won just one game in the opening set.

But she recovered to claim a 1-6 6-4 6-2 victory and earn a quarter-final clash against top seed Ons Jabeur or Anastasia Potapova.

The 24-year-old, ranked No. 93 in the world, is into just her second quarter-final of the season and her first since reaching the semis in Hobart back in January.

There were breaks aplenty in a topsy-turvy match, with Kenin breaking seven times and Volynets eight times.