On Sunday afternoon, the Dallas Cowboys and the Denver Broncos, both fresh off home wins in Week 1, meet at Denver's Sports Authority Field at Mile High.

The line opened at Cowboys -1.5, but has since risen a point to 2.5. That means Vegas thinks the Cowboys will win by 2.5 points. The Over-Under, or total number of points Vegas thinks will be scored in the game, is 43, up a half-point from where it opened.

Both teams used defense to win Week 1. The Cowboys held the NFC East rival Giants to a field goal, while the Broncos blocked a field goal that would have tied the score with one second left to beat the Chargers.

Before you make any bets on a game like this featuring two strong teams, you'll want to hear what former Vegas bookmaker Micah Roberts has to say.

When the Cowboys hosted the Giants last Sunday, Roberts told SportsLine's users to go Under 47.5. The result: a 19-3 Cowboys win and the easiest Under ever. It was his fifth win in six picks on Cowboys games.

Now, he's going for six wins in seven tries, and he's sharing his strong pick over at SportsLine.

Roberts knows that just because both defenses were dominant last week doesn't mean this week's game goes Under 43. The Chargers did put up 21 points on the Broncos on Monday night and the Giants were without stud receiver Odell Beckham Jr.

Against the Giants, Cowboys RB Ezekiel Elliott ran for over 100 yards and continued to show his dominance as a receiver, hauling in five catches for 36 yards. Roberts knows the Broncos were 28th against the run last season (130.3 yards per game), which plays into the Cowboys' main strength.

Broncos RBs C.J. Anderson and Jamaal Charles, meanwhile, combined to rush for more than 120 yards on Monday night. QB Trevor Siemian looked more than capable, hooking up with Bennie Fowler III for two touchdowns and rushing for a third.

And if you're a fan of defense, every defensive score counts for the Over-Under too.

Roberts knows there's one huge x-factor that determines whether the game ultimately goes Over or Under. And he's sharing his confident pick on the game over at SportsLine.

So which side of Cowboys-Broncos should you take? And is this game going Over or Under? Visit SportsLine now to see what huge x-factor determines the point total of Cowboys-Broncos and see what team has a surprising edge you need to take advantage of, all from the Vegas legend who's nailed five of his last six picks on Cowboys games.