In this weekend's box office battle between youth and age, age pulled an upset victory. Newly-minted 18-year-old action star Alex Pettyfer was widely expected to take the weekend with aliens-on-the-run spectacle 'I Am Number Four,' but the victory went to 58-year-old serious-thespian-turned-action star Liam Neeson, whose 'Unknown' debuted at No. 1 with an estimated $25.6 million over the four-day weekend.

'Unknown' was successfully marketed as an international thriller similar to 'Taken,' Neeson's hit from this time two years ago. That movie enjoyed a three-day opening of $24.7 million, and 'Unknown' was in the same ballpark, with $21.8 million from Friday to Sunday. And Neeson's age-appeal was no small reason for 'Unknown's' success. Studio research indicated that a full 54 percent of the film's audience was over 50.