Scarlett Johansson's Lucy beats Hercules in battle for US box office

'Lucy' punches her way to the top spot at the box office in Scarlett Johansson's best debut yet

Scarlett Johansson in Lucy

Scarlett Johansson's science-fiction thriller 'Lucy' climbed to the top of the US box office, taking in $44 million in its opening weekend.

'Lucy', which has received mixed reviews, stars Johansson as a woman who is kidnapped and implanted with a drug that unleashes her untapped brainpower.

This allows her to control time, learn Chinese in 60 minutes, kill bad guys in high heels and deliver some vicious beatings.

The film, directed by Luc Besson, easily beat 'Hercules', which also premiered over the weekend, starring Dwayne 'The Rock' Johnson as the son of god Zeus.

'Hercules' made $29 million, a weaker than expected debut in US and Canadian cinemas, but saw stronger ticket sales worldwide coming in at $28.7 million.

'Dawn of the Planet of the Apes', the latest instalment of the action franchise that sees men and apes clashing in a battle for survival, came in third with $16.4 million, bringing its total to $172.1 million.