The last San Francisco’s loss came more than 3 months ago when they lost to KC on Oct 23rd. They haven’t missed a step despite playing their third quarterback of the season, including Brock Purdy.Its gonna be tough to rush the ball for the Eagles against a stout 49ers defense that led the league in scoring defense, second in rushing yards allowed per game and second in yards per carry allowed (3.4) is going to be a challenge. 
Coach Shanahan is very good as an underdog and San Francisco stands 1st in scoring defense as they give up an average of 16.3 points per game. I also give the Special Teams edge to SF with a kicker who has never missed in the playoffs. Take the points and San Francisco as they find a way to get the win on Sunday in Philly.