While not without its cheesy moments, what Infernal Affairs captures so well is the jittery energy of a divided city, where everyone lives a double life or works two jobs just to get by.

Besides providing Damon with a rare villainous role, William Monahan’s knotty script invests much more time in its secondary characters, who bring a larger-than-life, almost cartoony aspect to the proceedings.

Yet this isn’t really a film about determinism, it’s a dick-swinging contest between some of the best actors in the business. Nicholson’s character is so hyper-masculine he wields a huge black dildo, Sullivan is impotent and Costigan is asked, “What, do you got your period?” when he orders a cranberry juice at the bar.

Somehow, Mark Wahlberg’s perpetually furious Sergeant Dignam (sample dialogue: “Maybe. Maybe not. Maybe f**k yourself.”) almost walks off with the film. Full credit to Vera Farmiga for holding her own as the police psychiatrist torn between sensible but distant Sullivan and sexy but damaged Costigan.

The only other women featured are nuns and prostitutes – perhaps Scorsese/Monahan should tell that to their therapists.

When The Departed won four Academy Awards, including Scorsese’s first ever best director Oscar, it came as something of a shock because Oscars best pictures aren’t usually this much fun. But if The Departed has one major flaw, it’s that it only ever feels like a movie, albeit an excellent one. Infernal Affairs, despite its flaws, always feels real.

It is almost unheard of that two equally good films spring from the same source, complementing and commenting on each other, yet that’s what has happened here. One’s small and intimate, the other brash and expansive. Watch Infernal Affairs and The Departed back to back, and you have the perfect double bill.

In this monthly feature series exploring Asia’s impact on international cinema, we examine how the continent’s directors have fared in Hollywood, whether its most popular films survived the remake process – and at what cost.