Can the Ravens be beat? Sure, of course; any and every team in the NFL can and will be beat again before the season is over.
Will the Pats beat the Ravens? I have no idea. To me the game could easily go either way, so a victory by either team would not be a shock to me. I felt the same way at the beginning of training camp about this matchup, the same at the start of week one, and the same now.
The matchup between the Pats offense versus the Ravens defense is both teams strengths. NE ranks #11 in yards and #1 in points; Baltimore's defense is #3 in yards allowed and #4 in points against. Considering the points scored on special teams and by the defense, that looks like a slight advantage to the Ravens.
Baltimore's offense is 19th in yards, 22nd in points. The Pats defense is 29th in yards, 26th in points. Statistically, again it looks like a slight advantage for the Ravens.
If you want to go a little deeper than those whole numbers, here is Football Outsiders' DVOA:
NEP Pass Offense #1, 65.6%
BAL Pass Defense #14, .07%
NEP Run Offense #2, 25.9%
BAL Run Defense #17, -4.5%
BAL Pass Offense #13, 18.8%
NEP Pass Defense #24, 20.1%
BAL Run Offense #8, 6.4%
NEP Run Defense #22, 2.8%
However, the Pats do have the edge on special teams. NE is 2nd on kick returns while Baltimore is 24th. Not much difference in punting, punt returns or field goals.
So what does a game like this often come down to? Turnovers - and here the Pats do have a decided edge. Pats are +4, 6th best in the NFL; the Ravens are -6, with only SF having a worse turnover ratio.
Since each offense and defense seem to be somewhat evenly matched up against their opponents defense and offense, if just one of those units can dominate the other, then that would probably be enough to win the game since all the other units would need to do is play even with their opponent. I'm cautiously optimistic about this game; neither a loss nor a win would surprise me. Should be a good game.