Czech Barbora Strycova defeated popular Serbian Ana Ivanovic 7-6 (7-5), 6-3 on Thursday, with the quarter-final win only adding to the box office woes of the Dubai Tennis Championships.
The number 47 came from behind in a tiebreaker to win the first set in an hour, then recovered from an early break down in the second to eventually thwart the comeback effort of her former number one opponent.
"I was trying to be aggressive because the conditions on this court are really fast," the winner said.
"I believed myself today, and I changed some things before I went on court. I lost my previous matches against Ana, so I had to change a little bit the return.
"It feels great, I'm happy about it. I'm happy the way I played,"
Strycova now takes on France's Caroline Garcia, who won her first match against Germany's Andrea Petkovic 6-3, 6-4.
"I'm playing Caroline tomorrow. She's a young gun, I'm looking forward for that," Strycova said.
The second semi-final will pit Italian Sara Errani, the 2013 finalist, against Ukrainian Elina Svitolina.
Errani had to struggle past American Madison Brengle, earning a hard-fought 4-6, 6-1, 6-4 win after almost two and a half hours. The match featured 39 break chances with 17 converted
Svitolina beat American CoCo Vandeweghe 6-4, 1-6, 6-2
"Good start, then I was struggling a bit," Svitolina said. "I think it was just something in my head. I was just somewhere not on the court.
"I'm really happy I could find a way to start third set well. But I needed to go through tough times and tough opponent today, because she was feeling really confident after winning second set."
Dubai earned a dubious record this week as the first WTA or ATP event to lose all eight seeds without any of them winning a match.
The defeats and the pre-tournament pullouts of world number one Serena Williams and Australian Open winner Angelique Kerber were body blows to the event, which also serves as a sponsor of the WTA itself.
There were also concerns about the no-show of Caroline Wozniacki, who claimed injury but was seen on the red carpet this week in New York at the Sports Illustrated Swimsuit awards.