Aryna Sabalenka displayed all the hallmarks of a Grand Slam champion by fighting back to defeat holder Jelena Ostapenko and reach the Dubai Duty Free Tennis Championships quarter-finals on Wednesday. Sabalenka has been unstoppable so far this season, winning each of her previous 12 matches to start the year, collecting a title in Adelaide and achieving her major breakthrough at the Australian Open. But the world No 2 found herself in unfamiliar territory against defending Dubai champion Ostapenko as the Latvian played lights out tennis to race into a 6-2 lead. Sabalenka quickly regrouped, though, to dominate the remainder of the match, sealing a 2-6, 6-1, 6-1 victory in one hour and 41 minutes. “I mean, she played unbelievable tennis in the first set,” Sabalenka said. “I wasn't ready for that fast tennis. She was just getting everything, and everything was in. “I don't know, magically I turned around this match, started playing even more aggressive, step in a little bit, put her under pressure, especially on her serve. It's worked well. Just super happy with this win.” Scare survived and win No 13 of the year secured, the second seed stays on course for a final showdown with world No 1 Iga Swiatek, who was once again in sensational form to ease into the last eight. Swiatek faced a potentially tricky opponent in 14th seed Liudmila Samsonova, a player in form who was narrowly beaten by Belinda Bencic in the Mubadala Abu Dhabi Open final this month. But the gulf in class between Swiatek and much of the rest of the WTA Tour was evident once again as the Polish top seed required just 71 minutes to record a 6-1, 6-0 victory. Outside of Sabalenka, Swiatek's toughest test in Dubai could come in the quarter-finals, where she meets former world No 1 Karolina Pliskova. The unseeded Czech dominated sixth seed Maria Sakkari in the second round, and followed that up with a hard-fought 7-5, 6-7, 6-2 win over Ukraine's Anhelina Kalinina. The winner of that blockbuster quarter-final will face an American in the semi-finals. Madison Keys, another dangerous unseeded player, has been carving her way through the draw, adding 15th seed Victoria Azarenka to her list of vanquished opponents in Dubai. Keys, who thrashed fourth seed Caroline Garcia in the previous round, outclassed the Belarusian 6-2, 6-1. Her quarter-final opponent has experienced a decidedly different tournament so far. Handed a bye into the second round, fifth seed Coco Gauff then received a walkover into the quarter-finals after Wimbledon champion Elena Rybakina withdrew due to a back injury. It proved to be a difficult day for former champions as at the opposite end of the draw, Ostapenko's exit was preceded by a defeat for 2019 winner Belinda Bencic. The Swiss eighth seed, who won the Mubadala Abu Dhabi Open title and reached the quarter-finals in Doha last week, saw her impressive Middle East swing halted by Karolina Muchova 6-1, 6-4. The Czech world No 112 will face third seed Jessica Pegula for a place in the semi-finals after the American shrugged off a topsy-turvy performance in the second round to claim a comfortable 6-3, 6-4 win over Romania's Ana Bogdan.