The American football season is back at the US box office - the second sporting film in three weeks has scored a touchdown at the top of the movie charts. DWAYNE 'THE ROCK' JOHNSON's new movie GRIDIRON GANG, in which he plays the coach of a prison team, opened at number one yesterday (17SEP06) with a $15 million (GBP8.3 million) opening weekend. Hollywood couple Scarlett Johansson and Josh Hartnett's new movie, The Black Dahlia, debuted at number two with a $10.4 million (GBP5.8 million) opening. And another sporting film, EVERYONE'S HERO - CHRISTOPHER and DANA REEVE's final animated project - debuted at three with $6.1 million (GBP3.4 million). SCRUBS star Zach Braff's modern romantic drama, The Last Kiss, also debuted high at number four with an opening weekend take of $4.7 million (GBP2.6 million). Last week's number one movie, THE COVENANT, slipped to number five on the new box office.