Alison Riske saw off Zarina Diyas at the Hobart International on Thursday and will be the only seeded player in the semi-finals.
Alison Riske claimed a comfortable 6-3 6-0 victory over second seed Zarina Diyas to book her place in the Hobart International semi-finals on Thursday.
Diyas' struggles on her own serve were a major contributing factor to her downfall, as she lost four service games in the opening set compared to Riske's two.
That trend continued into the second - Diyas dropping three games as Riske sailed to victory.
The American is now the only remaining seed in the WTA International tournament, where many players had to play twice on Thursday due to troublesome weather conditions earlier in the week, with Camila Giorgi and Robert Vinci also crashing out.
Ninth seed Vinci fell to Great Britain's Heather Watson 7-6 (7-0) 6-2, missing out on the chance to tackle Riske in the last four.
Third seed Giorgi, meanwhile, suffered a 6-1 3-6 6-2 defeat to Kurumi Nara of Japan.
After struggling on her own serve in the opening set, the Italian recovered well to claim the second.
However, Giorgi squandered eight break points on her way to losing the decider, and it is the Japanese who goes on to face Madison Brengle in the next round.
Brengle and opponent Karin Knapp had come through second-round matches against Kateryna Kozlova and top seed Casey Dellacqua respectively earlier in the day, but had to pick themselves up to go again for a place in the semi-finals.
Knapp initially showed no ill-effects of having gone three sets with the tournament's top-ranked player, but eventually succumbed to a 6-7 (7-3) 6-4 6-4 defeat.