NEW YORK — Guardians of the Galaxy Vol. 2 rocketed to an estimated $145 million debut. It kicked off Hollywood's summer movie season with something the movie business has been lacking: a sequel more successful than the original.

Studio estimates released Sunday said James Gunn's second Guardians film opened 54% higher than the 2014 runaway hit. That release debuted with $94 million in its first weekend.

Once a little-known, oddball property in Marvel's vault, the Guardians of the Galaxy have grown into one of the comic-book factory's biggest brands.

Disney validated Guardians, too, by moving it to the first weekend in May, the start of the lucrative summer movie season.

Fearing the might of Guardians, no other major studio releases debuted over the weekend.

Final figures are expected Monday.

PHOTOS: Guardians of the Galaxy Vol. 2 premieres in Atlanta