The former Wimbledon champion, seeking her second title of the season following her Brisbane triumph, breezed through the opening set in double quick time by unleashing her big serve and heavy groundstrokes.
But eighth seed Samsonova had other ideas and went ahead 4-1 in the second set, mixing up her power game with deft drops shots before levelling at one set apiece to keep alive hopes of a fifth win over the Moscow-born Kazakh in as many meetings.
Rybakina ramped up the pressure and grabbed a break in the fourth game of the decider after an untimely double fault by Samsonova and there was no looking back as the world number five wrapped up the contest.
"It was a really tough battle," Rybakina said. "Really happy I managed to win in the end. I started pretty well. A few shots went my way. It was going really well.
"In the second set the focus and energy went down a bit. Liudmila always plays very aggressive. It's not easy to play against her."
Earlier, seventh seed Kasatkina also shook off a mid-match blip to move into her second final of the season with a 6-3 4-6 7-6(2) victory over Beatriz Haddad Maia in an absorbing contest lasting nearly three hours.
"Beatriz is a huge fighter, one of the biggest on tour. Her level of giving everything on court is just incredible. She was not giving me anything for free. I had to earn this," Kasatkina said after an 83-minute final set.
"Really happy and a bit exhausted, but it was a great match. I hope every one enjoyed it."
The Russian dropped serve twice in the opening set but took full advantage of her sixth-seeded opponent's struggles to break four times and wrest the early advantage in the match.
Haddad Maia rediscovered her rhythm, however, and led 4-2 in the next set before Adelaide runner-up Kasatkina squandered the opportunity to draw level and allowed the 27-year-old to take the contest into a decider.
The breaks continued to flow in the final set, where the rallies seemed never-ending, but Kasatkina raised her game in the tiebreak to quell the challenge of Haddad Maia.
