Later, Palin came on stage during the Weekend Update mock news segment and bobbed to the beat as cast member Amy Poehler performed a rap song the Alaska governor decided was too hardcore for her to perform personally.
"I'm Jeremiah Wright 'cuz I'm the preacher; I got a bookish look and you're all hot for teacher," Poehler rapped as actors dressed as Eskimos, Palin's husband, Todd, and a moose pranced across the stage.
The appearance was anticipated since September, when Fey began portraying Palin just after GOP presidential nomineeselected the little-known governor as his running mate. The two look alike, and Palin remarked that people often told her - before Fey started portraying her - that she resembled the actor.
In the show's opening, Fey's impersonation of Palin told a group of reporters, "First off, I just want to say how excited I am to be in front of both the liberal elite media as well as the liberal regular media. I am looking forward to a portion of your questions."
Moments later, the camera cut away to the real Palin watching a television monitor alongside the show's executive producer, Lorne Michaels.
"You know, Lorne, I just don't think it's a realistic depiction of the way my press conferences would have gone," Palin said. She said she wished he would have let her do a sketch about "30 Rock," the NBC program in which Fey now stars. That prompted Michaels to deadpan: "Honestly not enough people know that show."
Palin then stood mute as Fey's "30 Rock" co-star, Alec Baldwin came onto the stage, mistook Palin for Fey and pleaded with Michaels not to let the actor go onstage with the governor.
"This is the most important election in our nation's history and you want her, our Tina, to go out there and stand with that horrible woman?" Baldwin said.
When Michaels broke down and introduced him to Palin, Baldwin feigned embarrassment and replied, "I see. Forgive me. I feel I must say this: You are way hotter in person."
Palin got even by saying, "Thank you, and I must say, your brother Stephen is my favorite Baldwin brother."
The camera soon cut back to Fey who answered a question about the polls.
"I don't worry about the polls. Polls are just a fancy way of systematically predicting what's going to happen. The only poll I care about is the North Pole, and that ... is ... melting. It's not great."
The real Palin then walked onto the news conference set, sending Fey fleeing.
"Thank you, thank you," the governor said to applause from the studio audience. "No, I'm not going to take any of your questions, but I do wanted to take this opportunity to say, `Live from New York, it's Saturday Night."'
On Sunday, NBC learned it scored its highest ratings for the late-night show in 14 years, in an estimate based on the nation's biggest media markets. Nothing has done better since skater Nancy Kerrigan visited after her Olympics drama with Tonya Harding in 1994.
Nielsen Media Research won't have a complete count of Saturday's audience until later in the week. It will likely be around 14 million people and 17 million for the first half hour, when the opening skit happened.
McCain, who spent Saturday night in Ohio, watched clips of the broadcast on Sunday. He told a crowd in Woodbridge, Va., on Saturday that he thought Fey and Palin were "separated at birth."