The 10th seed Elise Mertens and Anett Kontaveit had double duties on Wednesday in Sydney, winning their first round matches before facing each other in round two that the Belgian won 6-3, 6-1 in 66 minutes for the place in the quarters, scoring her second straight win over the Estonian.
Both players created nine break points but it was Mertens who had the upper hand in the crucial moments, saving seven of those and winning more than 60% of the points against a pale opponent, breaking her six times to sail through the encounter and hit the last eight.
They traded breaks at the start of the match and Mertens saved six break points in the rest of the set to keep the pressure on her rival, earning a break in game six before closing the set with a hold at 3-0 in game nine.
Kontaveit had nothing more left in the tank, suffering four breaks in the second set and handing the win to her rival who will now face Ashleigh Barty in the battle for the place in the semis. The 5th seed Petra Kvitova has secured the clash against Angelique Kerber thanks to a 7-6, 6-2 triumph against Su-Wei Hsieh in an hour and 36 minutes, scoring her third win over Hsieh in as many matches.
The Czech served at 70% and despite some problems on her second serve she held everything under control in own games, fending off seven out of eight break points and stealing almost half of the return points to earn no less than 13 break points.
Su-Wei did a fine job in repelling 10 of those but it wasn't enough for a more positive result, dropping the tie break and not playing with the same intensity in set number two to push Petra over the finish line. The Czech saved a break point in the opening game of the match and she fired a return winner to move ahead in the following game, having a chance to create a 5-1 gap in game six before Hsieh saved two break points to stay within one break deficit.
Kvitova wasted a set point on the return in the eighth game and she broke back in the following game to prolong the set, saving a set point at 5-6 to set up a tie break. Kvitova secured it with an ace in the ninth point, moving ahead after 55 minutes and gaining the momentum before the rest of the encounter.
A return winner sent Petra ahead at the beginning of the second set and she blasted another one in game five to extend her lead, painting a backhand down the line winner in game eight to complete the triumph and set a blockbuster clash with Angelique Kerber on Thursday.
Yulia Putintseva halted the 4th seed Sloane Stephens 3-6, 7-6, 6-0 in two hours and three minutes after a roller coaster ride, overcoming a 6-3, 5-3 deficit and dominating in the decider to send the American packing. Stephens did everything right for a set and a half, winning the opener with a single break in game four and breaking at love at the start of the second to hold the strings of the match firmly in her hands.
Putintseva started to fight back, securing her first break in game four before Sloane earned another one a few minutes later to come on a verge of victory. Still, she couldn't make that one last push, getting broken in game 10 while serving for the match and losing the tie break 7-4 to send the momentum to the other side of the net.
An impressive comeback provided a huge boost for Yulia and she was the only player on the court in the decider, winning 24 out of 33 points to claim all six games and book the place in the quarter-final against Kiki Bertens. Wednesday's results:
Second round results:
Elise Mertens (BEL) vs Anett Kontaveit (EST) 6-3 6-1
[Q]Yulia Putintseva (KAZ) vs Sloane Stephens (USA) 3-6 7-6(4) 6-0
[Q]Aliaksandra Sasnovich (BLR) vs [Q]Priscilla Hon (AUS) 0-6 6-3 6-3
Timea Bacsinszky (SUI) vs [WC]Samantha Stosur (AUS) 5-7 6-4 6-3
[5/WC]Petra Kvitova (CZE) vs Su-Wei Hsieh (TPE) 7-6(2) 6-2
First round results:
Anett Kontaveit (EST) vs [LL]Monica Puig (PUR) 2-6 7-5 6-1
Elise Mertens (BEL) vs [Q]Katerina Siniakova (CZE) 7-6(4) 2-6 6-2