Petrova, returning to the court after saving Russia from elimination in Sunday's second singles, and Vesnina registered a 7-5, 7-6 victory, claiming the second-set tie-breaker 7-1, to lift Russia into the final against Italy.
Winning two critical matches on Sunday was especially sweet for the 25-year-old Petrova, who felt she squandered chances in a three-set singles loss to Williams on Saturday.
“I was very disappointed after losing to Venus when I had everything in my hands and then I broke down,“ said Petrova. “I couldn't ha-ndle the nerves and the pressure.
“So, I thought, OK, I'll let it go. So today I got to do everything...make it up to them. I did it today. It just feels great. It feels fantastic.”
Williams was also playing her second match of the day after beating Anna Chakvetadze 6-1, 6-4 in Sunday's opening singles.
“I definitely felt good going out there,” the 27-year-old Williams said. “It was just a couple points here and there. I felt like I missed some shots that I should have made.”
The triumph put Russia into the final against holders Italy, who also needed a victory in doubles on Sunday to defeat visiting France in their semifinal.
Also stepping up for Russia was 20-year-old Vesnina, who hit three winners and an ace in the tie-breaker.
“It's one of the best moments in my life. I was so nervous before the match,” said Vesnina, who credited Petrova with giving her confidence. “This match was just unbelievable, just incredible.”
Entering Sunday's action tied at 1-1, Williams gave the US team a 2-1 lead by beating Chakvetadze.
After 41st-ranked Meilen Tu lost to Petrova 6-1, 6-2 to level the tie at 2-2, US captain Zina Garrison called on Williams to replace Vania King as Raymond's partner.