The second-seeded Serb - the highest seed in the draw after Angelique Kerber's withdrawal through injury before the tournament started - wasted little time in ending her Romanian opponent's run in Dallas.
She now faces surprise package Casey Dellacqua for a place in the final after the Australian continued her good form this week with a straight-sets dismantling of Aleksandra Wozniak.
Dellacqua followed up impressive victories over Yanina Wickmayer and Irina Begu with a 6-2 6-1 win over the Canadian to move within a victory of her first WTA Tour singles final.
Third seed Roberta Vinci survived a tough first set against Chanelle Scheepers to prevail 7-6(1) 6-2 and book her place in the other semi-final.
There, she will meet Bojana Jovanovski of Serbia, who progressed after sixth seed Peng Shuai retired from their match while trailing 6-4 1-0.
- Angelique Kerber
- Casey Dellacqua