It is the first work to emerge from the agency since Micro-soft moved the £60 million European creative account out of Bartle Bogle Hegarty in May as part of a global realignment.
The 30-second ad, which breaks this week, opens on a man sitting in a darkened room. He says: "I thought we were ready. The chopper came in hard and safe. The target was in our sights."
As he speaks, we see scenes from the game.
Suddenly, a woman comes in and switches on the light to reveal the man sobbing in front of his TV.
The voiceover states: "Rainbow six 3: their lives in your hands. It's good to play together."
The TV spot will run on Channel 4 and five along with all major satellite channels until Christmas.
The campaign targets men aged 16 to 34. Press ads will run across specialist gaming titles and men's lifestyle magazines including FHM and Maxim. A radio version will air on the Galaxy network, Kiss and Xfm.
The TV commercial was written and art directed by Gary Marjoram and Rob Brown. It was directed by Christophe Williams for Igloo. Media planning and buying for the campaign was by MJ Media.
Microsoft launched the Xbox console in March 2002 with a retail price of £299. Last month, Microsoft cut the price to £129.99, which is the same price as the Nintendo Game Cube, its main rival for second place in the console market behind the PlayStation 2.