The Patriots used the first to soar past the Bills, scoring touchdowns on six consecutive second-half drives, getting 35 points in just under 13 minutes to rout Buffalo 52-28.
The 49ers employed the latter, suffocating the New York Jets 34-0, yielding only 145 total yards and forcing four turnovers Sunday.
Coming off losses, New England and San Francisco found the touch that makes them favourites in their conferences this season.
For the Patriots, that means Tom Brady tearing apart an opponent.
"Down 21-7 and on the road, backs against the wall, and I thought we showed a lot of heart," Brady said. "That's what this team is made of. And we're going to battle until the end, I know that."
There wasn't even a skirmish at the Meadowlands, with the 49ers handing the Jets their worst home shutout loss since 1989.
"After the last game some people questioned us," said defensive end Aldon Smith, who had two sacks. " We know what we are capable of. We are a good defence that plays well together."
Also Sunday, it was Green Bay 28, New Orleans 27; Atlanta 30, Carolina 28; Arizona 24, Miami 21, OT; Houston 38, Tennessee 14; Philadelphia 19, N.Y. Giants 17; Minnesota 20, Detroit 13; Denver 37, Oakland 6; Washington 24, Tampa Bay 22; St. Louis 19, Seattle 13; San Diego 37, Kansas City 20; and Cincinnati 27, Jacksonville 10.
Monday night, it's Chicago (2-1) at Dallas (2-1)
Week 4 began with Baltimore's 23-16 victory over Cleveland. The Ravens are 3-1, the Browns are 0-4.
Indianapolis (1-2) and Pittsburgh (1-2) had byes.
PATRIOTS 52, BILLS 28
At Orchard Park, N.Y., Brady finished 22 of 36 for 340 yards and three scores, and also scored on a 4-yard run in helping the Patriots (2-2) avoid their first three-game losing streak in 10 years. Stevan Ridley scored two touchdowns rushing and New England finished with 580 total yards in overcoming a 21-7 third-quarter deficit.
The Patriots forced six turnovers, including four interceptions of Ryan Fitzpatrick, and three sacks.
Fitzpatrick finished 22 of 39 for 350 yards and four touchdowns, including two to tight end Scott Chandler.
The Bills (2-2) dropped to 1-17 in their last 18 games against New England.
49ERS 34, JETS 0
At East Rutherford, N.J., Carlos Rogers returned a fumble 51 yards for a touchdown, and San Francisco ran for more than 200 yards.
Frank Gore, Kendall Hunter and backup quarterback Colin Kaepernick — on a wildcat-style option — all ran for scores as the 49ers (3-1) bounced back from a loss at Minnesota. Rather than head back to the West Coast, coach Jim Harbaugh chose to have his team stay in eastern Ohio — and it apparently helped.
The Jets (2-2) lost top wide receiver Santonio Holmes to what appeared to be a serious left foot injury.
PACKERS 28, SAINTS 27
At Green Bay, Wis., the Saints' woes multiplied when Garrett Hartley had a field goal erased by a holding penalty, then missed a 48-yarder inside the last three minutes.
Drew Brees threw for 446 yards with three touchdowns for the winless Saints (0-4). Brees has thrown at least one touchdown in 47 straight regular-season games, tying the NFL's all-time mark set by Johnny Unitas.
But his team's season is spiraling out of control, even if Brees remains optimistic:
"It stinks. But despite where we're at right now, I think this team's going to do something."
Aaron Rodgers threw a go-ahead touchdown to Jordy Nelson in the fourth quarter, and Green Bay (2-2) shook off a week's worth of officiating controversy. Rodgers threw for 319 yards with four touchdowns and an interception.
FALCONS 30, PANTHERS 28
At Atlanta, the ranks of Falcons doubters were slimmed because of a stunning comeback capped by Matt Bryant's 40-yard field goal with 5 seconds remaining.
The Panthers (1-3) seemed ready to win on Cam Newton's run with just over a minute remaining, but he fumbled while trying to dive for a first down. Carolina recovered and wound up punting, downing the ball at the Atlanta 1. Then Matt Ryan, who threw for three TDs, connected with Roddy White on a 59-yard pass.
Four plays later, Bryant won it for the Falcons, off to their best start since 2004, when they reached the NFC championship game. Carolina had seven sacks, 3 1/2 by Charles Johnson.
CARDINALS 24, DOLPHINS 21, OT
At Glendale, Ariz., the Cardinals kept three streaks going. They moved to 4-0 for the first time in 38 years by earning their 500th regular-season victory; they played in Chicago and St. Louis before moving to the desert. They have won eight straight at home. And they won their fifth straight home overtime game when Jay Feely kicked a 46-yard field goal 6:31 into overtime.
Arizona forced overtime when Kevin Kolb threw a 15-yard touchdown pass on fourth down to Andre Roberts with 22 seconds to play in regulation.
"It's not luck, I can tell you that," coach Ken Whisenhunt said. "It can't be luck as many times as we've been successful with that."
The winning field goal came after rookie QB Ryan Tannehill was hit by Paris Lenon as he threw and Kerry Rhodes came up with an interception.
Tannehill threw for 431 yards. Brian Hartline set a Dolphins record with 253 yards receiving on 12 catches.
TEXANS 38, TITANS 14
At Houston, the Texans moved to 4-0 for the first time in their 10-year history. Danieal Manning and Kareem Jackson returned interceptions for touchdowns and Matt Schaub threw two TD passes.
Arian Foster had a touchdown run for the Texans (4-0).
Titans quarterback Jake Locker left in the first quarter and did not return after hurting his left, non-throwing shoulder on a hit by Glover Quin.
"It's always toughest part of playing any game when you have to stand on the sideline and watch your team compete and you're not able to be out there with them," Locker said.
Matt Hasselbeck threw two touchdown passes in relief of Locker for the Titans (1-3), but also was picked off twice. Chris Johnson carried 25 times for 141 yards, more than tripling his rushing total through the first three games.
EAGLES 19, GIANTS 17
At Philadelphia, the Eagles maintained their mastery over the Giants with their eighth win in the last nine in the series. Lawrence Tynes missed two field-goal tries from 54 yards with 15 seconds left for the Giants (2-2).
LeSean McCoy had 121 of his 123 yards rushing in the second half for Philly (3-1), which has gotten those victories by a total of four points. Alex Henery kicked a 26-yard field goal with 1:49 left and the Eagles overcame two pass interference penalties on New York's final drive.
"It's just the Giants and Eagles," McCoy said. "This is what it comes down to.
VIKINGS 20, LIONS 13
At Detroit, the return teams were very special for Minnesota (3-1) and atrocious for the hosts.
Percy Harvin returned the opening kickoff 105 yards for a touchdown and Marcus Sherels scored on a punt return early in the third for Minnesota. The Vikings matched the number of wins from last season and snapped an 11-game losing streak in the division.
The Lions (1-3) have lost three straight and became the first team since at least 1940 to give up a kickoff and a punt return for TDs in consecutive games, according to STATS LLC. They gave up scores on a kickoff and punt in last week's 44-41 loss in overtime at Tennessee.
BRONCOS 37, RAIDERS 6
At Denver, Peyton Manning made it quite clear there's little reason to fret about his passing. Manning threw for 338 yards and three touchdowns in a vintage performance.
Manning opened the game by leading the Broncos on an 80-yard touchdown drive — their first opening-quarter touchdown of the season — and Denver (2-2) never trailed in beating the Raiders (1-3) at home for the first time since 2007.
"It's hard to play against Peyton Manning no matter what," said Oakland coach Dennis Allen, whose defence was missing both starting cornerbacks. "He's a Hall of Fame quarterback and there's a reason he's a Hall of Fame quarterback.
Willis McGahee ran for 112 yards for his 32nd-career 100-yard game.
REDSKINS 24, BUCCANEERS 22
At Tampa, Fla., Billy Cundiff's 41-yard field goal with 3 seconds remaining won it after he'd missed three earlier kicks.
Thanks to some late-game playmaking by rookie quarterback Robert Griffin III, the Redskins (2-2) rallied after blowing a lead.
Griffin threw for 323 yards and rushed for 43, including a 5-yard TD run. Fellow rookie Alfred Morris rushed for 113 yards, including a 39-yard score.
Tampa Bay (1-3) wiped out an 18-point deficit to go ahead 22-21 on Connor Barth's third field goal, a 47-yarder with 1:42 remaining.
RAMS 19, SEAHAWKS 13
At St. Louis, the strong leg of rookie Greg Zuerlein was on display. He made a club-record 60-yard field goal and a 58-yarder, becoming the first kicker to make a 50- and a 60-yarder in one game.
"Right now, our kicker is the MVP of the season," running back Steven Jackson said. "Pretty much, all we've got to do is get across the 50-yard line and we're in his range."
The Rams (2-2) went ahead 10-7 late in the first half when a fake field goal attempt turned into a 2-yard touchdown pass from punter Johnny Hekker to Danny Amendola. The Rams intercepted Russell Wilson three times.
The Seahawks (2-2) lost six days after beating Green Bay when a botched call by replacement officials on the final play gave them the winning touchdown. Regular officials were back this weekend.
Marshawn Lynch led Seattle with 118 yards on 20 carries, including an 18-yard score on the game's first series.
CHARGERS 37, CHIEFS 20
At Kansas City, the Chargers (3-1) stayed atop the AFC West with a one-sided win thanks to six takeaways — three interceptions in the first half and three fumble recoveries.
Philip Rivers threw for 209 yards and two touchdowns, and had only five incompletions.
Dwayne Bow had 108 yards receiving for Kansas City (1-3), but Jamaal Charles, who followed his big game last week at New Orleans with touchdowns rushing and receiving, fumbled twice.
BENGALS 27, JAGUARS 10
At Jacksonville, the Bengals (3-1) moved into a tie with Baltimore atop the AFC North thanks to six sacks, even though four cornerbacks were sidelined: starters Nate Clements and Leon Hall, as well as backups Jason Allen and Dre Kirkpatrick.
Andy Dalton threw for 244 yards and two touchdown passes and ran for a score.
The Jaguars (1-3) got only 38 yards rushing from Maurice Jones-Drew.
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