Monsters vs Aliens was the decided victor at the weekend box office, reeling in $58.2 million. The haul eclipsed Watchmen's $55 million debut as the biggest so far in 2009.
Opening way back in second place was ghost tale The Haunting in Connecticut, which scared up $23 million, good enough to bump last week's No. 1 thriller-fest Knowing to third ($14.7 million).
The weekend's other new release, 12 Rounds, shot in at seventh ($5.3 million) behind I Love You, Man (No. 4, $12.6 million), Duplicity (No.5, $7.5 million) and Race to Witch Mountain (No. 6, $5.6 million).
Watchmen saw another big drop 60 percent to land in eighth. But its $2.75 million take was enough to push it past the $100 million threshold.
Rounding out the top 10 were Taken (No. 9, $2.7 million) and The Last House on the Left (No. 10, $2.6 million).