Australian Open champion Kenin suffers early exit from Qatar Open

America's Sofia Kenin, 21, was eliminated from the Qatar Open by Dayana Yastremska in straight sets on Tuesday. Photo by Dean Mouhtaropoulos/Getty Images

Australian Open champion Sofia Kenin crashed out of the Qatar Open on Tuesday, suffering a straight-sets defeat to Dayana Yastremska.

Kenin's serve was broken early in the first set and the American failed to recover as her Ukrainian opponent claimed the frame 6-3.

Kenin, 21, started the second set stronger by breaking Yastremska's serve for a 2-0 lead, but was soon broken twice herself.

World No. 5 Kenin broke back as the pair battled towards a tiebreak, and it was Yastremska who emerged victorious in the back-and-forth decider for a 6-3, 7-6 (4) win.

Meanwhile, world No. 1 Ashleigh Barty progressed with a 6-3, 6-2 victory over Laura Siegemund of Germany, and No. 3 seed Karolina Pliskova also advanced with ease, beating America's Bernarda Pera 6-3, 6-0.

No. 4 seed Belinda Bencic saw off Veronika Kudermetova 6-4, 4-6, 7-6 (4) after two hours and 41 minutes on court, while Australian Open finalist Garbine Muguruza breezed past Ajla Tomljanovic 6-1, 6-2.

Two-time Wimbledon champion Petra Kvitova also secured her spot in the next round, coming from behind to beat Spain's Carla Suarez Navarro 4-6, 6-3, 6-0.