Casey Dellacqua has gone down in straight sets to former world No.1 Jelena Jankovic in their Texas Open semi-final on Thursday.

In the lead-up to next week’s US Open, Australia’s Dellacqua fought hard before losing 7-5 6-4 to Serbian Jankovic, who will play Italy’s Roberta Vinci in the final.

“I’ve had a great wk here in Dallas,” Dellacqua tweeted after the loss.

“Fought hard but JJ was too good tonight. So excited to be heading to NY tmrw for the #USOpen2012”

The 27-year-old Queenslander surrendered a 40-0 lead on her own serve with the scores tied at 4-4 in the second set, as the former world No.1 set up a clash with Italy’s Roberta Vinci in the final.

Jankovic paid tribute to Dellacqua’s efforts.

“It was a battle out there, Casey played real well,” Jankovic said.

“There were a lot of tough games and points. It’s never easy to play a left-handed player. It has been a long time since we played each other. I hung in there and stayed positive and made it in two sets.”

Italian Vinci cruised past Serbia’s Bojana Jovanovski 6-0, 6-0 in a rare double-bagel at tour semi-final level. Vinci has won three of her six tour titles in the past year.

Jankovic, who hasn’t claimed a tour singles title since 2010, has won all three of her past matches against Vinci, with the most recent on hard court at the US Open first round in 2009.