In contrast, second-seed Goerges who beat Slovakian Viktoria Kuzmova 6-1, 7-6 (8/6) in her semi-final has not faced one seeded player all week.
Defending champion Julia Goerges is bidding to become just the third back-to-back ASB Classic victor in tournament history, following Patty Fendick (1988-89) and Eleni Daniilidou (2003-04).
"I guess Auckland just brings the best out of me", said Andreescu, who needed only 81 minutes to beat Su-Wei.
Despite the distraction of a blustery wind, Bouchard seemed headed for an upset over the tournament second seed when she won the first set.
The 37-year-old Williams, who turned pro six years before Andreescu was born, is ranked 39th in the world.
US House passes bills that would end government shutdown, without wall funds
Democrats also approved, 241-190, a separate measure funding the Agriculture, Interior and other departments through September 30. Trump has said the partial shutdown, which began December 22, will last "as long as it takes" to get the funding he wants.
The world No 28, 33-year-old Hsieh is renowned for her crafty play, with an often expert ability to take the pace off the ball and use the angles of the court.
"What's really important for me is to stay in the present moment and I've been doing that all week and I'm beyond grateful right now".
"This week I've been playing a lot of different types of game styles".
For her troubles, the world number 152 now faces seven-time Grand Slam victor Williams in the quarter-finals.
With a place booked in the final, Andreescu is also eyeing a qualifying spot in the Australian Open main draw because her ranking is not high enough for direct entry. "So for me it's not about giving up, it's about finding solutions and trying to find a way to get a victor". But I think I prepared very well before this match.
With her opponent increasingly misfiring and her own confidence growing, Andreescu would build a 5-0 lead in the decisive set, only for the seven-time Grand Slam champion to reel the score back in to 5-3.