An unusual thing happened on Monday at the U.S. box office. After being out of the top spot at the U.S. box office for the last 10 days, Guardians of the Galaxy moved back into the #1 position on its eighteenth day of release.

On Monday, Guardians of the Galaxy knocked Teenage Mutant Ninja Turtles out of first place and finished atop the U.S. box office with a gross of $2.884 million. Teenage Mutant Ninja Turtles finished in second place with a gross of $2.801 million. Let’s Be Cops took third place with $2.103 million, and The Expendables 3 took fourth place with $1.320 million.

Guardians of the Galaxy’s return to the top demonstrates exactly how strong word of mouth is for the film and how many fans are returning for multiple viewings. With its current pace, Guardians of the Galaxy should pass Transformers: Age of Extinction sometime in the next week to become the highest grossing summer movie of the year. Guardians of the Galaxy also has a good chance at passing The Lego Movie and Captain America: The Winter Soldier to become the highest grossing film of 2014 so far.

Not bad for a film that many were predicting would be Marvel Studios first big flop.