The Patriots pass defense once again struggled to prevent big plays.
A high-powered offense that rarely turns the ball over had just three points and was forced into two turnovers during the first half. It opened the second half with two more turnovers that led directly to touchdowns for the 49ers, turning a 17-3 deficit into a 31-3 rout in the blink of an eye.
On the whole, the Patriots offense turned the ball over four times, and had a fifth overturned on review. It also turned the ball over on downs on a crucial 4th-and-2 in their own territory to seal the team's fate late in the fourth quarter. What is it with Bill Belichick-coached teams and failed fourth-quarter, 4th-and-2 conversions in their own territory?
A normally solid special-teams unit allowed a successful fake punt in the first half and a 62-yard kickoff return in the fourth quarter to set up the game-winning score after the team had stormed back from the 28-point deficit to tie the game at 31.
In all three phases of the game, the Patriots fell short. A turnover-prone offense and a special-teams unit that allowed two big plays put the Patriots' shaky defense in several vulnerable positions.
The Patriots defense was able to bail out the rest of the team on three occasions by forcing a fumble deep in the red zone after Brady's first interception, a turnover-on-downs after a Shane Vereen fumble and then a failed field-goal attempt after the successful fake punt.
The Patriots defense also did a respectable job against the 49ers vaunted running attack, holding it to 3.9 yards per carry when removing the 31-yard fake punt from the equation.
Yet once again the lack of a pass rush and problems in the secondary showed up to doom the Patriots. The 49ers drove down the field with ease for a six-play, 63-yard touchdown drive that ended with an easy 24-yard touchdown pass to Randy Moss to open the game.
The 49ers had a three-play, 80-yard touchdown drive in the second quarter that was keyed by a 35-yard pass interference penalty on cornerback Aqib Talib for failing to play the ball and capped off with a 34-yard touchdown pass to a wide-open Delanie Walker.
On the play directly after Brady's second interception of the night in the third quarter, the 49ers appeared to put the game away with a 27-yard touchdown pass to Michael Crabtree, putting the score at 31-3.
Alas, the Patriots offense finally found their rhythm, and the defense forced three consecutive punts to give the offense the ability to come all the way back to tie the game.
With the score tied at 31, the Patriots defense gave up its final big play of the night. The Patriots sent a big blitz that didn't get home, cornerback Kyle Arrington missed a tackle on Crabtree, and he was off to the races for the game-deciding 38-yard touchdown.
Add it all up and the Patriots defense allowed four touchdown passes of 20 yards or more and 8.6 yards per passing play, with the pass rush getting to quarterback Colin Kaepernick for just one sack on 26 dropbacks.
On the season, the Patriots defense has now allowed a league-most 68 passing plays of 20 yards or more and 7.8 yards per pass attempt—fifth-worst in the league.The pass rush has yielded sacks on just over five percent of opponent pass attempts, good for just No. 25 in the league.
The Patriots defense does a respectable job against the run, and they're No. 2 in the league in takeaways. Their ability to stop the run and force turnovers has put them in the middle of the pack in points allowed at 22.5 per game. Allowing 22 points to most opponents gives the Patriots plenty of cushion, because the offense is typically so dominant.
However, the Patriots defense is simply not good enough to win a game against a good team when the offense doesn't show up. The Patriots can only beat good teams by outscoring them; they can't win left-handed by relying on their defense to win the game.
The Patriots had the same issues with their pass defense last season, and they still managed to get to the Super Bowl. However, the goal is to win the Super Bowl, not just get there, and it's hard to imagine the Patriots winning it all with a pass defense this easy to expose.