The San Francisco 49ers moved to 8-0 for just the second time in their history as quarterback Jimmy Garoppolo enhanced their Super Bowl claims by lifting them to a 28-25 win at the Arizona Cardinals.
A dominant defence and power running game had fired the 49ers to their surprising unbeaten start, but questions had been raised about Garoppolo's credentials despite his impressive record as a starter.
Tom Brady's former back-up answered them in some style on Thursday night though, throwing for 317 yards and firing four touchdowns to earn a tight win.
After four wins last season, San Francisco started the new campaign as 40/1 shots to win the Super Bowl, but are now 5/1 joint-second favourites to lift the Vince Lombardi Trophy alongside the New Orleans Saints.
Fellow unbeaten side the New England Patriots remain the favourites to defend their title.
With the Cardinals loading up on the line to stop San Francisco's running game, Garoppolo was forced to win the game with his arm, but proved more than capable as head coach Kyle Shanahan allowed his team to pass the ball more than run it for the first time this season.
Garoppolo also showed poise, in a road game, and was spectacular on crucial third downs, completing 12 of 14 pass attempts and hitting three touchdowns.
"That's usually where quarterbacks earn their money," Shanahan said. "You can do a lot of things on first and second down. You can mix in run or pass to even out the game, but on third down, that pass rush is coming.
"They always have their best coverages and blitzes called. You need a good guy back there. Everyone knows how well he can throw, but he was on tonight throwing and he got to the right spots, and when it wasn't there, he made plays with his legs."
Kenyan Drake's touchdown on his Cardinals debut gave his side an early 7-0 lead before the 49ers responded with scores from George Kittle and Kendrick Bourne.
KeeSean Johnson and Andy Isabella also went over for the Cardinals, while touchdowns from Emmanuel Sanders and Dante Pettis helped keep the 49ers in front.
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