In the end, “Iron Man 2” didn’t have the mettle to seriously challenge the opening-weekend record set by “The Dark Knight” two years ago (in July, when school was out).

Paramount’s whopping $133.6M estimate for “IM2” puts it in fifth place among three-day openings, following “TDK” with $158.4M, “Spider-Man 3” ($151.1M), “The Twilight Saga: New Moon” ($142.8M) and “Pirates of the Caribbean: At World’s End” ($135.6M).

As next month’s “Twilight” will carry a hefty 3-D surcharge in many locations, its opening will most likely dwarf that for “Iron Man 2,”which did not benefit enough from soaring ticket prices to break any records.