I mean dude, you can literally lose to any team in the playoffs. The games are likely to be close no matter who you play.
The Rams will be playing a completely different Cowboys team too. The offense had not yet unlocked its potential at that point and Dallas still beat them by 23.
Something else worth noting is that the Rams have been feasting on bad teams in the second half of their schedule. NY, NO, WASH, and ARI account for 4 of their 6 wins on this streak. Two of their wins have come by a single point. They are a fine team, but really nothing more than that.
If this team can't even beat the Rams in round 1, they had no business being considered a contender.