Veronika Kudermetova upset the Doha Open seedings to defeat American teenager Coco Gauff 6-2, 3-6, 6-1 on Thursday and set up a semi-final with world number one Iga Swiatek.

Russian 25-year-old Kudermetova, ranked eighth, needed just over two hours to complete victory over the world number four.

If she is to reach a first WTA final since Istanbul last April, Kudermetova will have to get past a refreshed Swiatek.

The reigning French and US Open champion reached the last-four when last weekend's Abu Dhabi title winner Belinda Bencic withdrew from their quarter-final.

Kudermetova, who will be playing in her second semi-final of the year, is yet to win a set from Swiatek in two previous encounters.