The final match of the evening saw American Lauren Davis prevail over compatriot Sloane Stephens, in a fluctuating and highly entertaining three set match on centre court.
Stephens started with a hiss and a roar to take the first set before Davis came back to upset the sixth seed 1-6 6-4 6-1 in an hour and three quarters.
The first set was all one-way traffic with Sloane dominating through her power and speed on her feet.
Davis competed well in some extended rallies but was found wanting across the court while Stephens maintained her energy and a ruthless focus.
However, Davis responded positively in the second set, lifting her efforts and gradually working her opponent down by winning some lengthy rallies with improved shot selection.
Her tenaciousness earned rewards and after staying level with Stephens she broke out to a 5-4 advantage and held on to win the set 6-4.
She carried that momentum into the third, going up 3-0 as Stephens looked a far cry from the confident player that began the match.
Stephens finally got moving to make it 1-4 but that was as close as she got with Davis clinching the set 6-1.
Earlier, Hometown favourite Marina Erakovic has been knocked out of the ASB Classic after losing a hard-fought match to Czech Barbora Zahlavova Strycova today.
Strychova took the first set with Erakovic fighting back strongly in the second, before she was eventually overcome 6-0 6-2 6-4.
The Stanley Street crowd threw their support behind Erakovic but it wasn't enough as her rival hung in to close out a tensely fought match that took almost two and a half hours.
For the sixth year straight the Kiwi has failed to advance beyond the tournament's second round, after last making the quarterfinals back in 2008.
Zahlavova Strycova was a figure of frustration early in the third set and had to put aside an angry exchange with the umpire over a questionable line call and realign her focus. She kept her cool and improved her serve and played the big points well to negate Erakovic's enthusiasm.
In the final service game Erakovic had two break point opportunities that she couldn't convert before the tournament's fourth seed sealed victory on her first match point.
Venus Williams also breezed into the quarterfinals by dispatching Japan's Kurumi Nara 6-4 6-1 in just over an hour.
It was the perfect workout for Williams on a scorching afternoon in Auckland; Nara put up some resistance in the first set, before being completely overwhelmed in the second.
Williams finished the match with aplomb, smashing a fierce winner down the line past a dejected Nara.
The American served poorly by her standards - only a 48% first serve percentage - but never really came close to being broken by the World No44 Nara. In contrast, the Japanese player had to fend off ten break point opportunities, four of which were taken by Williams.
The 34-year-old Williams will face Elena Vesnina in the quarter finals. The Russian took care of Croatian teenager Ana Konjuh 6-3 6-1 earlier today while the other completed second round match saw American Coco Vandeweghe beat last year's semi finalist Kirsten Flipkens 6-1 6-7 (5) 7-5.
