Swiatek posted her 40th victory of the season in one hour and 42 minutes and remains on course for a potential quarter-final showdown with top seed and three-time Wuhan winner Aryna Sabalenka.
"We know each other pretty well, so I just wanted to focus on being consistent and playing as good as possible," Swiatek, the seventh seed, said of Frech.
"I know she is running to every ball always and sometimes using the power of the opponent, so I wanted to not play too crazy but play solid and I’m happy that I did that," said Swiatek, who is chasing a qualification spot for the year-end WTA Finals.
Despite the lopsided scoreline, the opening set was tight, lasting over an hour and requiring Swiatek to erase a 0-2 deficit and save seven of eight break points before she finally took the lead on her fourth set point.
Upping the pressure with her relentless forehand, Swiatek claimed a 10th game in a row to build a 4-0 advantage in the second set.
The former world number one briefly lost momentum, getting broken by Frech, but recovered to advance to the round of 16, where she awaits one of two lucky losers, Lanlana Tararudee or Ashlyn Krueger.
British world number 170 Sonay Kartal, who missed six months this year with a spinal stress fracture, upset ninth-seeded Belinda Bencic 6-0, 7-5 to book a date with Jasmine Paolini or Nikola Bartunkova.
