Sloane Stephens lost in the first round of the Dubai Championship on Monday, the latest setback for the American rising star who reached the Australian Open semifinals.

Stephens, who has risen to 16 in the world rankings after knocking out Serena Williams in Melbourne, lost to Sorana Cirstea of Romania 5-7, 6-3, 6-2.

Last week, Stephens lost to Klara Zakopalova in the third round of the Qatar Open.