The title was the 21st of Swiatek's career as the world number one sounded out a warning to her rivals ahead of this month's French Open where she is a three-time champion.
"After Madrid I knew it would not be easy. It can always go both ways," Swiatek said. "Thank you (Sabalenka) for sharing the court with me and pushing me to be better."
Swiatek broke Sabalenka twice in the first set where the Belarusian conceded 12 unforced errors in a lopsided start to the match. Sabalenka fought back, reaching five break points in a bid to lead 2-0 in the second, but Swiatek held her own serve.
Sabalenka failed to break again with Swiatek holding her nerve to save two break points on her next serve. The set progressed to 3-3 before the Pole broke again, in back-to-back games this time, ensuring her path to victory.
"I love this tournament... I'll come back stronger next year and hopefully win the trophy," Sabalenka said as she congratulated Swiatek. "I hope we make it to the final at Roland Garros and I will get you there."
In response, Swiatek said: "We will see about the Roland Garros final."
The French Open starts on May 26th.