Gauff had beaten Swiatek in their last meeting, in the semi-finals at Cincinnati, to end a seven-match losing run against the Pole before going on to capture her maiden grand slam title at the US Open.
The US teenager arrived in Beijing in red-hot form.
But Swiatek, who surrendered her place at the top of the world rankings to Aryna Sabalenka after losing to Jelena Ostapenko in the fourth round of the season's final grand slam at Flushing Meadows last month, regained her grip on her rivalry with Gauff to reach a seventh final this year.
"I'm really happy with my performance," Swiatek said.
"It feels like I can play freely again. It's been a while since I felt that way.
"I'll remember for the rest of my career that even though tougher times may come, in your mind you can always overcome that. With hard work, you can achieve it.
"I'm happy I switched my attitude after the US Open, and hopefully I'll be able to keep it for as long as possible."
The 22-year-old did not face a single break point during the first set, which she eased through in 40 minutes with a typically strong display from the back of the court.
Swiatek put early pressure on Gauff in the next set and surged to 2-0 with an early break before her American opponent held serve and took a medical timeout to address a niggling shoulder problem.
The four-times major champion barely stepped off the gas after the restart and completed the victory in style to stay on course for her first WTA 1000 title of the season and a tour-leading fifth trophy this year.
Up next for Swiatek is Samsonova, who beat former Wimbledon champion and this year's Australian Open beaten finalist Elena Rybakina 7-6 (9-7) 6-3 to improve her head-to-head record over the Moscow-born Kazakh world No.5 to 4-0.
"Every time it's a battle with Elena ... she's a champion," Samsonova said.
"It's unbelievable to be (in the final)."
The 24-year-old Samsonova, ranked 22 in the world, has now beaten three former grand slam champions in Beijing with victories over two-time Wimbledon winner Petra Kvitova and the 2017 French Open victor Ostapenko in earlier rounds.
- with AP
