Top seed Mirra Andreeva battled her way through to the semi-finals of the Linz Open by winning an entertaining encounter against Sorana Cirstea.

The first career meeting between the two players was keenly contested, with a back-and-forth clash on Friday lasting for two hours and 17 minutes before Andreeva prevailed 7-6 (7-4) 4-6 6-2.

A close opening set saw Andreeva strike first with a break in the third game, but Cirstea soon fought back to level the match at 4-4.

The Romanian, who recently announced this will be her last season on the WTA Tour, then successfully defended a break point at 5-5 on her way to forcing a tie-break.

However, it was Andreeva who emerged triumphant from the breaker, helped by moving 5-2 ahead in a fast start that left her opponent with too much to do.

It was not a straightforward path to victory for the Russian from there, though, as Cirstea immediately broke in the opening game of the second set and later struck again to race into a 4-1 lead.

Andreeva reduced the deficit, but Cirstea was able to serve it out to force a decider.

In the final set, it was Andreeva who made the fast start, breaking early and winning each of the first three games.

Cirstea again managed to respond, breaking to bring the match back on serve at 3-2, but Andreeva then showed her quality as she reeled off three straight games, including two breaks, to prevail.

Andreeva will now face another Romanian, Elena-Gabriela Ruse, in the last four.

In the first match of the day, Ruse came from behind to earn a surprise win over fourth seed Jelena Ostapenko, triumphing 4-6 6-4 6-1.

Data Debrief: Andreeva ends quarter-final woe

Andreeva will be relieved to get through this one after suffering significant frustration at this stage of multiple recent tournaments.

The 18-year-old had lost seven of her last eight quarter-final matches on the WTA Tour, but she can now put that troubling sequence to the back of her mind after claiming an important victory.

In a close match, both players struggled for consistency on serve, with nine breaks in total (five for Andreeva and four for Cirstea).

Andreeva only won 59 of her 94 points on serve, with Cirstea similarly struggling with 55 from 94 as the momentum continued to change hands until Andreeva's final surge took her over the line.