The top-seeded Hsieh and Peng were up a set and 3-1 on Garbiñe Muguruza and Carla Suárez Navarro before the Spaniards rallied to win the second set and go up 2-1 in the third. But from there, Hsieh and Peng reeled off five straight games for the 6-2, 5-7, 6-2 triumph that avenged a loss against Muguruza and Suárez Navarro in the Madrid semifinals last month.
The biggest statistical difference between the teams was second serve points won, with Hsieh and Peng winning 63% compared to just 29% for their opponents.
In more good news for Hsieh, she will rejoin her partner as doubles co-World No.1s on Monday's rankings. They were previously co-No.1s for one week last month.
No.2 seeds Errani and Vinci had an easier time of it in their semifinal, as after dropping the first two games against Lucie Hradecka and Michaella Krajicek they won nine straight games en route to a 6-2, 6-1 victory. Second serve percentage was also a key factor in this one, with Errani and Vinci winning 71% and Hradecka and Krajicek just 39%.
The Italians have surrendered just four games in their last two matches and are now 16-1 the last three years here, having been champions in 2012 and runners-up in 2013. They are also 16-1 on clay this year, with the lone loss coming by virtue of retirement in Rome. Finally, they are 11-0 in Grand Slam play this year - having won January's Australian Open.
"It's an unbelievable feeling for us to be in the final at Roland Garros for the third year in a row," Vinci said. "We have played a lot of matches in the last few weeks, which is good for our confidence and we are ready for this one. It will be a tough match, for sure. Hsieh and Peng are a very good team with a lot of experience. Even though Sara and I have played a few Grand Slam finals now, we will still be nervous - a Grand Slam final is a Grand Slam final! But we will do our best."
Hsieh and Peng will take a 2-1 record against Errani and Vinci into Sunday's final, including two straight wins - the most recent one coming in the 2013 Rome final.