Rapid Reaction: 49ers 45, Bills 3

Thoughts on the San Francisco 49ers' 45-3 victory over the Buffalo Bills at Candlestick Park in Week 5:

What it means: The 49ers improved to 4-1 and moved into a first-place tie with Arizona in the NFC West. They won at home for the eighth time in a row during the regular season. Their deep passing game came alive for the first time this season. San Francisco set a single-game franchise record with 621 yards on offense. The 49ers finished this game with a 300-yard passer (Alex Smith), a 100-yard rusher (Frank Gore) and two 100-yard receivers (Michael Crabtree and Vernon Davis). They appear primed for their Week 6 home game against the New York Giants, a rematch of the NFC Championship Game.

What I liked: Just about everything. The 49ers finished the game with 311 yards rushing and 310 yards passing. They have now outscored their last two opponents by a 79-3 margin.

The 49ers used play-action effectively to loosen up the Bills' defense in the early going. Not long after a holding penalty wiped out a play-action reception for Davis, the 49ers used the tactic to produce a 53-yard gain for the Pro Bowl tight end. Davis' reception was the longest for the 49ers this season. There was more to come. A 43-yard scoring pass to Kyle Williams and a 28-yarder to Crabtree helped Smith finish the first half with career highs for passing yards (237) and NFL passer rating (158.3, the highest possible). Smith's third-quarter deep strike to Davis up the right sideline could not have been thrown with any greater accuracy.

The 49ers' defense held the Bills to 204 yards. Its ability to force timely turnovers was important. Patrick Willis' forced fumble right before halftime set up Smith's 28-yard scoring pass to Crabtree. Chris Culliver's third-quarter interception killed a drive deep in 49ers territory. Those plays helped break out the game and prevent the Bills from rallying.

What I didn't like: Penalties against the 49ers, including one for what appeared to be a legitimate chop block call against Gore, wiped out big first-quarter gains for Davis and Crabtree. Other than that, the only thing I didn't like was the absence of a mercy rule. This one was ugly.

Smith tops 300: The 49ers quarterback owned two 300-yard passing games before Sunday. He had 303 yards in this game before giving way to Colin Kaepernick in the fourth quarter. Smith took a hard hit after passing while the 49ers were leading 31-3. He came through that hit OK, burned the Bills with a rushing play and then came out of the game.

Persistence on Kaepernick: The 49ers looked smart for using backup quarterback Kaepernick to great effect during a 34-0 victory over the New York Jets in Week 5. They didn't look so smart Sunday. Kaepernick lost a fumble in Bills territory on a run around the left side. San Francisco incurred a holding penalty against left tackle Joe Staley while Kaepernick was throwing deep and incomplete for Davis later in the game. The 49ers stuck with the overall idea, however, and Kaepernick came through with a 15-yard run to the Buffalo 1-yard line, setting up Gore's touchdown run.

Aldon Smith's chase: Second-year outside linebacker Aldon Smith needed 1.5 sacks to break Reggie White's sack-era record for fewest games needed to reach 20 career sacks. Smith got close at least twice, delivering a crunching hit on Ryan Fitzpatrick just after the quarterback threw. Smith later impressed with an open-field tackle on Bills receiver Stevie Johnson. Smith hasn't gotten many opportunities to prove himself as a base outside linebacker because so many opponents have used three or more wide receivers at a time.

What's next: The 49ers are home against the Giants in Week 6.