Defending champion Tsvetana Pironkova says her anger at being snubbed for a wildcard is the driving force behind her march to the semi-finals of the Sydney International.

The Bulgarian’s 6-4 6-1 win over Samantha Stosur’s conqueror Barbora Zahlavova Strycova on Wednesday night was her 14th successive victory at Sydney Olympic Park.

But the world No.67 admitted she was shocked at discovering once again she’d have to go through qualifying despite her success last year when she knocked off three top-10 rivals en route to the title.

Pironkova was ranked No.37 in the world – just five places below the direct entry cut-off – before being stripped of the points amassed last year and falling to No.67 this week.

“I applied but obviously didn’t get it,” she said.

“I was very disappointed about that. When I was back home, everybody was saying: `You’re going to get a wildcard. Don’t worry’.

“But it’s the decision that the tournament made. It’s obviously a big motivation when I came here to play well.”

Pironkova returned superbly against Zahlavova Strycova, who looked to be struggling in the hot conditions, breaking her opponent three times in the second set.

After last year’s memorable eight-match run, the 27-year-old said she felt confident whenever she set foot on Ken Rosewall Arena – the court where she won her one and only WTA tournament.

“I know the people, I know the court, I know the surface. I feel like almost at home here,” Pironkova said.

“I have positive emotions from last year and I’ve been here few times before that, so it’s very familiar to me. It’s a beautiful city.”

World No.22 Karolina Pliskova is also through to the semi-finals after seeing off Spain’s Carla Suarez Navarro 4-6 6-4 6-0.