鈥淭hor: Ragnarok鈥� thundered to one of the year鈥檚 best box-office debuts, opening with an estimated $121 million in North American theatres.

The robust debut for the third 鈥淭hor鈥� movie was a welcome shot in the arm for Hollywood and theatre owners who have just suffered through a terrible October at the box office.

鈥淭hor: Ragnarok鈥� also bucked the trend of diminishing returns for sequels. The 2011 鈥淭hor鈥� debuted with $65.7 million; 2013鈥檚 鈥淭hor: The Dark World鈥� opened with $85.7 million.

The big opening cements the unlikely breakthrough of New Zealand director Taika Waititi, who shepherded the $180 million production to Marvel鈥檚 best reviews since 2008鈥檚 鈥淚ron Man.鈥�

The weekend鈥檚 other new nationwide release was the holiday-themed comedy sequel 鈥淎 Bad Mom鈥檚 Christmas.鈥� It grossed $17 million over the weekend.

Jake Coyle, The Associated Press