Andreescu won 11 straight games against Williams after losing the first set and falling behind 1-0 in the second set.
Saturday's match will be her first semifinal at a WTA tournament, a feat she has achieved in memorable fashion.
Less than 24 hours after knocking off world No. 3 Caroline Wozniacki, the 18-year-old from Mississauga, Ont., downed the legendary Venus Williams 6-7 (1), 6-1, 6-3 in a quarterfinal on Friday at the ASB Classic.
"I know I have nothing to lose, this is my first WTA 250 [final] so I'm just going to try and enjoy every moment".
She blasted the 20-year-old Kuzmova off the court in the first set, with a number of winners and unreturnable serves.
Goerges is the defending champion and ousted Eugenie Bouchard of Westmount, Que., earlier in the week on her way back to the championship match.More news: United States warns citizens of arbitrary action in China
Goerges was in near ideal form as she raced through the first set in under 30 minutes with a power game that forced Kuzmova well behind the baseline.
"I believe that anything is possible and tonight I think I did the impossible", Andreescu said after beating Venus. "I wasn't really expecting to get this far but now I've beaten a couple of top players so my confidence is there, that's for sure", Andreescu said.
She beat top-seeded Wozniacki 6-4, 6-4 and sixth-seeded Williams 6-7 (7), 6-1, 6-3.
Against Wozniacki, Andreescu needed a medical time out at the start of the second set for her back injury but she still managed to chase down shots and win vital points. "I was still aggressive, but not aggressive as much as I wanted to be".
"Everybody deserves their spot in the final, so she has played some terrific tennis", Goerges said. Today she didn't serve as well as other matches I've seen her play.
"Canada has gone from being a minor nation in tennis", says Roth, "Sure, we've always had a few players who were good, to now being a legitimate force in the tennis world".