The robot boxers of Real Steel and the dancers of Footloose are in a tight fight for the US box-office title.
The Hugh Jackman tale about machines in the boxing ring took in 16.3 million dollars, which would make it the number one movie for the second-straight weekend, according to studio estimates.
But Real Steel came in barely ahead of the remake Footloose, which opened with 16.1 million dollars.
The movies are close enough that they could switch rankings once final numbers are released.
Studio estimates are based on actual business Friday and Saturday and projections for Sunday based on how well similar movies typically hold up.
An executive at Disney, which is distributing Real Steel for DreamWorks Pictures, said he expects his movie will come out on top because of strong family crowds during day-time shows on Sunday.
"Absolutely," said Dave Hollis, Disney's head of distribution. "The way we've been playing, the families who've been coming and the kind of day-time business we've had on each of the weekend days so far, we have the expectation that it won't be terribly close. They're free to estimate as they will, but we expect to be number one."
Paramount, which released Footloose, was tracking its movie's revenues slightly ahead of those for Real Steel, said Don Harris, head of distribution.
Universal's horror update The Thing, about Antarctic researchers stalked by a shape-shifting alien, opened at number three with 8.7 million dollars. Steve Martin, Jack Black and Owen Wilson's bird-watching comedy The Big Year, released by 20th Century Fox, flopped at number nine with a 3.3 million opening.