Paris, France, 7 June 2012 | AAP

Sara Errani is plotting another Italian job on Samantha Stosur, but Australia’s big French Open hope is having none of it.

Francesca Schiavone’s ambush of Stosur in the 2010 Roland Garros final still burns, leaving the Queenslander on high alert to Errani’s capabilities ahead of their semifinal showdown on Thursday night (starting 10pm AEST).

> see photos of Sam’s progress into the semifinals at Roland Garros

Errani has lost all five previous clashes with Stosur – including last month on Rome clay – but is arguably the most improved player in world tennis.

The 25-year-old has won 23 of 26 matches for a tour-leading three titles on clay this season, while her quarterfinal triumph over German 10th seed Angelique Kerber was her first success in 29 attempts against a top-10 foe.

The victory propelled Errani into her maiden grand slam semifinal and also ensured she will leapfrog Schiavone and Flavia Pennetta to become Italy’s new No.1 when the next rankings are released on Monday.

“I’ve had success against her in the past, but semifinals of Roland Garros is a whole new ball game,” Stosur said.

“This is probably the breakthrough year for her, making quarterfinals (at the) Australian Open and now here, French Open. You’ve got to respect that and be aware of that.

“You can think about the past and the history of the matches but, if something changes when you’re out on the court, you have to be aware of that and adjust, too.

“She’s a tough competitor and makes you work for it. I have to be ready for a tough match. I’m going to play aggressive and try and play my game.”

Stosur had also been unbeaten in four matches against Schiavone before losing their final in Paris two years ago and then again in a crucial Fed Cup tie last year in Hobart.

But the US Open champion insists she has no mental blocks against Italians.

“Whether they’re Italian, Japanese or Slovakian, it doesn’t bother me. It never really comes into the equation,” Stosur said.

“Obviously it’s just maybe built up here a little bit more now in the press conference with the Italians. They like to remind me that I played Francesca, who is an Italian, and that’s that.

“It’s totally irrelevant.”

Errani, at just 164cm tall, puts her amazing transformation this year to plain hard work and paying Wilson $US30,000 ($A30,900) to get out of a racquet contract in order to use a 1cm longer Babolat.

“A big change for me really was the racquet,” she said.

“That makes me feel much better in the court, makes me feel with more power and not too difference with other players on power and these things.”

The diminutive 21st seed is also renowned as one of the craftiest players on tour and admits pre-match tactics are a major part of her game.

“I don’t have too much power so I have to think more,” Errani said.

“I have to make other things maybe with the head … I have to be fast – I have to be resistant.”

If Stosur can get past Errani, she will face either Russian second seed Maria Sharapova or Wimbledon champion Petra Kvitova in the final.

Sharapova outclassed Kaia Kanepi 6-2 6-3 in Wednesday’s first quarterfinal before fourth seed Kvitova eliminated Kazakh qualifier Yaroslava Schvedova 3-6 6-2 6-4 to book a semifinal showdown with the world No.2.

Fox Sports 2 and Fox Sports 2HD will broadcast Stosur’s match live tonight from 10pm AEST. For more information, please see our TV Guide.