Not even Kryptonite could stop "Man of Steel" at the box office this weekend.
The Superman reboot racked up $21 million in Thursday night shows. Of that figure, $9 million came from midnight shows, while a series of 7 p.m. corporate group sale screenings brought in an additional $12 million.
Those results compare favorably to the summer's other superhero blockbuster, "Iron Man 3," which generated $15.6 million in midnight screenings last month. That comic book movie sequel went on to gross nearly $175 million in its opening weekend.
The Warner Bros. and Legendary Pictures release is on track to crack $100 million at the domestic box office over the next three days.
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"Man of Steel" will expand on Friday to 4,207 theaters, 3,350 of which will be 3D. That number also includes 331 IMAX screens. Warners will be able to tack on a hefty surcharge to many of the tickets it sells thanks to the fact that 80 percent of showings will come from 3D and IMAX screens.
Superman's box office muscles will be flexed abroad, as well. Warner Bros. is debuting "Man of Steel" in 24 foreign markets Friday, including the U.K., South Korea and Mexico.
Next weekend it will expand to another 26 territories, including major markets like China and Russia.
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The film carries a hefty $200 million production budget, but Warner Bros. film chief Jeff Robinov is already on record predicting it will be the biggest hit in the studio's history, so expectations are gargantuan.
Reviews have been mediocre, with the film earning a 58 percent "rotten" rating on the critics aggregator Rotten Tomatoes.
To relaunch the defender of truth, justice and the American way for more jaded modern audiences, Warners tapped "Dark Knight" director Christopher Nolan to produce the film and "300" director Zack Snyder to handle the behind-the-camera work. It also assembled an impressive cast. Henry Cavill stars as Superman, Amy Adams plays Lois Lane, Russell Crowe plays Superman's biological father and Michael Shannon is the villainous General Zod.