No.2 seed Simona Halep escaped surging No.7 seed Jasmine Paolini from a set and a break down in the Upper Austria Ladies Linz quarterfinals, triumphing 4-6, 7-5, 6-0 in 2 hours and 13 minutes.

Halep moves into her third semifinal of what has been an injury-struck season for her. This is the second tournament in a row that she has made the last four following the Transylvania Open two weeks ago. In the final event of her season, Halep remains on course to preserve her streak of winning at least one WTA title every year since 2013.

She did not have it easy for much of the match against Paolini. The Italian is in the best form of her career this autumn after collecting her maiden title in Portoroz in September. Since then, Paolini has also upset Elise Mertens in Indian Wells and reached the Courmayeur semifinals on home soil, and is now perched at a career high of World No.51.

Match momentum: Paolini got off to a strong start that left the crowd - and Halep - fairly stunned. The 26-year-old raced into a 3-0 lead after winning 12 of the first 14 points of the match, seven with clean winners as she slammed the ball around the court with irresistible panache.

But Paolini was unable to sustain her untouchable form. The first sign of vulnerability came when she lapsed into error and was unable to serve out the first set, though she immediately broke Halep to capture it anyway.

However, it was the beginning of a gradual turnaround that saw Halep grind out a knife-edge second set and then race through the decider as Paolini faded away.

Key stats: Paolini added to her seven winners in the first three games to tally 12 by the end of the second set. But that fell to seven in the second as she battled to find any way past Halep's defence, and just four in the third as she struggled to get on the front foot at all.

By contrast, Halep found just seven winners in the first set, but raised that number to 13 in the second and 12 in the third as she anticipated Paolini's patterns and was ready to counterpunch through them.

Turning point: Paolini seemed to have avoided two potential turning points in an arduous second set. She was unable to take a point for a 4-1 lead, instead sending a backhand wide to lose her break advantage - but seemed to have righted the ship with an authoritative hold for 4-3.

And at 4-4, she survived the most physically gruelling game of the match despite some supreme efforts by Halep to hold for 5-4.

But that game seemed to take its toll on Paolini. The steam went out of her game immediately afterwards, and Halep rattled through 12 of the next 13 points to snatch the second set.

In Halep's words: "I'm very relieved I could win this match - it was a very, very tough one. She played so fast, so powerful, at the beginning I didn't have time to do anything on court. But then I just tried to play a little bit of slice, a little bit changing the rhythm, then a little bit more aggressive, and in the end I was dominating the match."

What's next for Halep: An all-Romanian semifinal clash against Jaqueline Cristian, whom Halep defeated 6-1, 6-1 in the Cluj-Napoca quarterfinals two weeks ago. Cristian upset No.4 seed Veronika Kudermetova 6-3, 7-6(5), saving three set points in the second set, to reach the last four of a WTA event for the second time, following Nur-Sultan in September. At that tournament, she spoke about how Halep had been an inspiration to her countrywomen.

Cristian, who fell to Lesia Tsurenko in the final round of qualifying, also becomes the second lucky loser to reach a WTA semifinal in 2021, following Viktoriya Tomova in Belgrade.

Highlights: Cristian d. Kudermetova, Riske d. Wang Xinyu, Collins d. Van Uytvanck

Earlier, No.3 seed Danielle Collins and No.8 seed Alison Riske set an all-American semifinal in the top half of the draw. Collins, who had defeated Greet Minnen in the second round, bested her second Belgian in a row with a 7-5, 6-3 win over Alison Van Uytvanck. Riske followed by coming from 2-5 down in the second set to triumph over qualifier Wang Xinyu.