GTA IV has the potential to be one of few non-FPS games to dominate the list of most played Xbox Live titles, says Microsoft.
The game broke more records than we care to count on its launch earlier this week, and MS expects everyone who bought the game to give the multiplayer mode a shot.
Aaron Greenberg, director of product management for Xbox 360 and Xbox Live, said: "The multiplayer in this game is so well implemented that I can't imagine anyone owning a copy without trying to play it on Xbox Live."
Although it's typically first-person, willy-waving, shooters that dominate the Xbox Live scene, Greenberg points towards GTA IV's extraordinary mass appeal to drive it to the top spot over XBL giants Call of Duty 4 and Halo 3.
He said: "GTA is unique because it appeals to such a large audience. It will likely be the best-selling game launched all year and we expect it will drive a lot of new members to Xbox Live," he told Reuters.
Jon Hicks, editor of the Official Xbox 360 Magazine UK, told us: "It's immensely popular and the multiplayer is really good, so I can see it coming in on top."
But how long would it hold off the FPS big boys? "I wouldn't like to speculate on the longevity of its stay as number one online game. The Halo 3 and Call of Duty 4 communities aren't going anywhere, so it'll be interesting to see if a dedicated GTA player base will form to keep them off the top spot," he added.
IDC analyst Billy Pidgeon, suggested that GTA IV could "lead the way online for a large contingent of players who don't play first-person shooters".
It's going to be an interesting one.