Fresh off a nearly perfect run predicting the outcome of World Cup futbol matches, Microsoft’s digital assistant, Cortana, has focused her abilities on picking the winners of NFL football games.

Need help predicting whether or not the Seahawks will hold off the Green Bay Packers? Cortana thinks she knows. Ditto for the winner of the Atlanta Falcons versus the New Orleans Saints or the San Francisco 49ers versus the Dallas Cowboys games.

The kicker, of course, is that you’ll need access to Cortana, Microsoft’s digital assistant. And for right now, that means a Windows Phone 8.1 phone, either one that’s been upgraded via Microsoft’s developer program or as part of the ”Cyan” rollouts that Microsoft and its carriers are pushing to vanilla Windows Phone 8 Lumia phones.

Phrasing!

Of course, there a few wrinkles. For one, asking Cortana about the outcome of a particular game is a bit like a magic spell: You’ll need to ask Cortana “Who will win Team A or Team B?” and she will provide an answer. Microsoft’s example uses “the Seahawks” and “the Packers”; asking Cortana “who will win, Seattle or Green Bay?” doesn’t work. (So much for natural-language processing, at least for now.)

And as David Letterman says, remember, no wagering. In fact, Cortana doesn’t give you any information about the Las Vegas odds or point spread, so trying to figure out if the Pittsburgh Steelers will cover the 6-point spread against the Cleveland Browns is a tough call. You’d probably be better off using Cortana in a game that’s evenly matched—although presumably Cortana’s going to have a tougher time picking a winner.

Remember, Cortana uses oddsmakers to provide a reality check against its own data. Here’s how Microsoft explained it performed its calculations for the World Cup:

“For the tournament, our models evaluate the strength of each team through a variety of factors such as previous win/loss/tie record in qualification matches and other international competitions and margin of victory in these contests, adjusted for location since home field advantage is a known bias,” Microsoft said previously. “Further adjustments are made related to other factors which give one team advantages over another, such as home field (for Brazil) or proximity (South American teams), playing surface (hybrid grass), game-time weather conditions, and other such factors.”

Mark Hachman

Microsoft presumably has decades of information to pull from when calculating the outcome of NFL games, however. Recall that Cortana, along with most other analysts, predicted that the United States would never exit the World Cup’s “Group of Death.” But after it did so, Cortana was perfect through the knockout stage—with one exception, whiffing on the third-place game where The Netherlands defeated Brazil.

Cortana's picks for NFL Week 1

So with about a week to “prepare” before each NFL game, Cortana should be equally perfect, right? We’ll see. Here’s a quick rundown of some of the games, as called by Cortana: the Denver Broncos will win over the Indianapolis Colts, the Patriots will top the Dolphins, the Jets will beat the Raiders, and the Tennessee Titans will beat the Chiefs. Surprisingly, Cortana punted when I asked the winner of the San Francisco 49ers and Dallas Cowboys game. (Microsoft executives said on Twitter that this is a glitch, and should be fixed soon.)

Still,Cortana’s predictions should help fans sleep at night—or not. And if one team manages to overturn Microsoft’s digital oracle, well, it will really have scored an upset.

Updated at 11:36 with comment from Microsoft representatives on the state of the 49ers-Cowbos prediction.