Doha, Feb 14 : Three-time defending champion and former World No.1 Iga Swiatek returned to the semifinals with a 6-2, 7-5 win over Elena Rybakina in Thursday's quarterfinals here, recording her 15th straight win at the tournament overall.

In a rematch of last year's championship match, Swiatek came from 4-2 down in the second set, and saved two break points at 4-4, before eventually wrapping up a straight-sets victory in 1 hour and 36 minutes.

The win is Swiatek's 100th at WTA 1000 level in 121 matches played -- making her the second-fastest to the milestone after Serena Williams, who played 115 WTA 1000 matches to do it.

After beating Rybakina at last month's United Cup, Swiatek has now levelled her all-time head-to-head against the Kazakh to 4-4, and she continues on her quest to be just the second WTA player since 2000 to win four straight titles at a single event.

But Swiatek will need to get a first win in five tries against Jelena Ostapenko, the 2016 Doha finalist, for another spot in the final match. Ostapenko defeated Ons Jabeur in Thursday's third quarterfinal, 6-2, 6-2, to book her own spot in the semifinals. In another quarterfinal, unseeded Ekaterina Alexandrova stormed into the semifinals by stunning American sixth seed Jessica Pegula of the United States 4-6, 6-1, 6-1 in a one-hour 42-minute clash.

But the focus was on Swiatek as she was looking to set a couple of records. After a 36-minute first set, where Swiatek won the first three games and never faced a break point, Rybakina converted on her second chance in the opening game to set a new tone for the match.

What followed was an hour-long set in which Rybakina bent, but never broke -- at least at first. She saved two break points in her first service game to lead 2-0, and three more the next time she stepped to the line to extend her advantage to 3-1. But handed a sixth break point in the set at 4-3, 15-40, it was Swiatek's turn to come up with clutch play. As Rybakina charged the net off of a well-timed backhand, Swiatek whipped a forehand past her for the break back.

In the deciding game, Swiatek hammered a cross-court backhand return winner off of a short second serve to deny Rybakina a tiebreak, and the contest ended two points later when the No. 5 seed served up just her second double fault in the match overall.

While Swiatek will be hoping for her own sort of revenge when she faces Ostapenko next, the Latvian got revenge of her own with an easy dispatch of Jabeur in just 71 minutes after Swiatek sealed her own victory. Ostapenko lost to Jabeur last week at the WTA 500 Mubadala Abu Dhabi Open, 7-6(4), 7-5, which put her season's singles record at 1-4.

But with four straight-set victories this week, including upsets of No. 4 seed Jasmine Paolini and No. 16 seed Liudmila Samsonova, the 2017 Roland Garros champion has found her form in singles after starting the year with strong doubles runs like a runner-up finish at the Australian Open with Hsieh Su-Wei, and a win in Abu Dhabi with Ellen Perez.

/IANS