Alex Smith can’t possibly top the heroics of Saturday.

Five seasons of mediocrity and a solid 2011 can’t be forgotten after one unbelievable performance.

Sure driving the ball 85 yards in 88 seconds to beat the New Orleans Saints 36-32, with nine seconds remaining is incredibly impressive—and enough to make fans believe he can throw for 299 yards and three touchdowns again.

The difference is going to be in the opponent. The Saints' defensive deficiencies were masked by the brilliance of Drew Brees. In reality, they had few playmakers on the defensive and a pass rush that only had success when they had additional rushers from the secondary. Yet Smith still took four sacks and was hit seven times on Saturday.

Now they will be playing a New York Giants front four that is by far the best of the remaining four teams in the playoffs.

Nobody has a group of talent that includes three vicious rushers like Osi Umenyiora, Jason Pierre-Paul and Justin Tuck. In their 37-20 win over the 15-1 Green Bay Packers, Aaron Rodgers was on the run all day, literally. He had led the team in rushing yards, and was constantly flushed from the pocket. A quarterback is only as good as his protection.

Smith has to have time in the pocket or the offense is never going to have a play of over 20 yards. The 49ers don’t have an explosive talent on offense that can make something out of nothing. Receiver Michael Crabtree and tight end Vernon Davis need the ball delivered to them in stride to make a play.

Smith is more than capable of doing this with time, but on the run?

Not so much.

In the three losses the 49ers have suffered this season, Smith was sacked 20 times and hit 30 times. Remember Smith getting sacked nine times against the Ravens in a complete blowout?

Smith has had a special season after five years of failures. It’s a testament to his perseverance and belief in new Head Coach Jim Harbaugh to re-sign with the team in the offseason.

But when push comes to shove, Smith can’t perform with 300-pound ends chasing him down constantly. He doesn’t possess the rocket-fast delivery and quick decision-making skills to beat the Giants' pass rush.

With much more playoff experience and a better quarterback on their side, it’s hard to pick against the Giants next Sunday at Candlestick Park.

But the biggest reason to believe in the G-Men is their deadly pass rush that seems to be getting better by the week.

It’s been a heck of a ride for Smith, but his time is almost up.

Prediction: New York Giants 24, San Francisco 49ers 16