LUGANO, Switzerland - Polona Hercog came from a set down for the second time in as many days to make her first quarterfinal of the season at the Samsung Open presented by Cornèr, overcoming Sorana Cirstea 3-6, 7-6(0), 6-4 in two hours and 24 minutes.

The Slovenian had a slow start to 2019, losing her first four WTA main draw matches of the year, but has begun to round into form of late: in Miami, she pushed World No.2 Simona Halep to the brink of defeat in a gripping 5-7, 7-6(1), 6-2 loss, and yesterday the 28-year-old scored just her second Top 30 win since 2015 in eliminating No.2 seed Carla Suárez Navarro from Lugano. 

Today's result - from a narrowly contested match that featured 16 breaks of serve in total - seals the 2011 and 2012 Bastad champion's first WTA-level quarterfinal since her run to the last four of Bucharest last July, and continues her reversal of the head-to-head against Cirstea, to whom she lost their first three meetings. Hercog has now won two in a row against the Romanian - having also come back from a 3-6 first-set loss in Beijing qualifying last October.

However, it was Cirstea who shot out of the blocks today, firing winners off both wings and displaying judicious use of finesse in zooming to a 5-1 lead in just 20 minutes of play. The World No.103 even produced a brilliant forehand winner around the post - and though Hercog managed a brief fightback to cling on to the set, fine serving and a tally of 10 winners saw Cirstea over the line at the second go.

The second set was much harder to call, featuring a run of six consecutive service breaks, punctuated by a two-hour rain delay with Hercog leading 3-2. The 28-year-old's resistance at the end of the first set had enabled her to find her groove to an extent, particularly on her impressively heavy forehand, with which she bullied Cirstea around the court on a number of occasions.

For much of the set Cirstea was playing catch-up, but the 2009 Roland Garros quarterfinalist displayed real fortitude in clinging on, breaking back immediately three times as Hercog's groundstrokes oscillated between winners and errors. When the 29-year-old emerged from an error-strewn, three-deuce tussle to break for 6-5, momentum seemed to have swung her way.

But in keeping with the unpredictability of the set, it was Cirstea's accuracy that deserted her in serving for the match and in the ensuing tiebreak, while Hercog swept through 11 of the final 13 points - including running around her backhand to strike a swashbuckling return winner to break back, and winning a delightful cat-and-mouse contest en route to a tiebreak whitewash. In contrast to her total of three winners in the first set, Hercog had managed to total 17 in the second.

A rattled Cirstea was unable to regain her composure in time to begin the decider, dropping serve to love in the blink of an eye. But just as in the second set, the 2008 Tashkent champion valiantly hung on, producing one of the shots of the day in a backhand winner swung while chasing a lob - and, after a three-break sequence, came up with a strong hold to inch ahead 4-3.

Again, though, Cirstea was unable to sustain her lead. Instead, it was Hercog who rose to the occasion: having strung together a 12-point streak to close out the second set and begin the third, the Istanbul runner-up blitzed through another 12 consecutive points to snatch victory from 3-4 down. The Hercog forehand was spectacular in these closing stages - as was her movement and anticipation - and a fifth ace on match point sealed a fine win.

Next up for Hercog will be either No.7 seed Rebecca Peterson or Russia's Veronika Kudermetova, the latter of whom closed out first-round action earlier with a dramatic comeback over Jil Teichmann. Kudermetova had trailed by a 1-4 double break in the deciding set against the home favorite, and Teichmann had even held two match points when serving for victory at 5-4 - but the Guadalajara 125K champion found her range with her power when it mattered, and dominated the deciding tiebreak to come through 6-2, 4-6, 7-6(2).

Meanwhile, the streak of new champions on the WTA Tour is guaranteed to continue this week after Fiona Ferro upset No.4 seed Alison Van Uytvanck 6-4, 7-5. The Belgian, who took the Budapest trophy in February, was the last player standing in either Lugano or Bogota draw to have previously won a title this year - and so this weekend will see the 17th and 18th different winners of 2019 crowned.