Transformers: Revenge of the Fallen grossed $60.6m on its first day of North American release, according to a preliminary estimate from Paramount, making it the biggest Wednesday opener ever.

In the international marketplace the film had taken an estimated $78.5m by the end of Thursday. That total included takings from the UK and Japan, where the film opened last week, and from the 58 territories in which it opened on Wednesday.

The Paramount-DreamWorks sci-fi action sequel started screening in North America just after the stroke of midnight on Wednesday (June 24), and the first day figure includes $16m for its late-night showings. Over the course of the day the film played in 4,234 theatres.

The $60.6m gross beats the current record for an opening Wednesday, the $44.2m earned by Harry Potter and the Order of the Phoenix in July 2007. And if confirmed it will rank as the second biggest opening day overall, after the $67.2m achieved last July by The Dark Knight (which opened on a Friday) but just ahead of the $59.8m taken by Spider-Man 3 (also on a Friday) in May 2007.

The powerful start puts the sequel, again directed by Michael Bay and starring Shia LaBeouf and Megan Fox, on course to achieve the biggest five-day North American opening starting on a Wednesday. The current record-holder is Spider-Man 2, with $152.4m. (The biggest five-day opening starting on any day is the $203.8m scored by The Dark Knight.)

The original Transformers opened on a Monday in July 2007 and took $156.5m over its first seven days (which included the July 4 holiday weekend). It went on to gross $319.2m in North America and $389m internationally.