The two talent competitions were scheduled against each other in the 8pm hour last night, in which The Voice scored a total of 10.7 million viewers to The X Factor's 7.5 million - a difference of 3.2 million.
Preliminary ratings also show that while both scored a 3.3 in the demo rating overall, The Voice led in their shared 8pm hour alone with a 3.3 to The X Factor's 2.7.
The ratings win for The Voice still showed a decline across the week from Monday's premiere episode.
The X Factor's second hour scored 9.49 million, giving the show an average of 8.47 million in the two primetime hours.
Simon Cowell publicly complained last week about NBC's decision to programme The Voice directly against The X Factor.
"These guys have really got it in for us. It's nothing short of dirty tricks," Cowell said.
"The reason they've done this is they don't want people to see X Factor because they've heard how good the series is. They don't want their audience to see Britney Spears. They don't want their audience to see Demi Lovato."
His comments drew a response from Voice coach Blake Shelton, who urged Cowell to stop "mouthing off".
"Every time I turn around, he's mouthing off about our show. It's like, 'Do your own show! Come on! Put something together there and do your thing'," Shelton declared, adding: "We'll just do ours and we won't mouth off about you!"
The Voice continues Monday at 8/7c on NBC. The X Factor USA continues tonight (September 13) at 8/7c on Fox.