Buffalo Bills tight end Dawson Knox (88) is hit by San Francisco 49ers free safety Jimmie Ward during the second half of Monday night's game in Arizona. (AP photo)

GLENDALE, Ariz. (AP) — Josh Allen threw for 375 yards, tied a career high with four touchdown passes and the Buffalo Bills stayed in sole possession of first place in the AFC East with a 34-24 victory over the San Francisco 49ers on Monday night.

Buffalo (9-3) moved a step closer to winning its division for the first time since 1995 thanks to a nearly flawless performance from Allen. The 24-year-old quarterback was stellar against the 49ers, completing 32 of 40 passes with no interceptions.

He threw touchdown passes to Cole Beasley, Dawson Knox, Isaiah McKenzie and Gabriel Davis as the Bills built a 17-7 halftime lead and controlled the majority of the second half.

The Bills are one game ahead of the Miami Dolphins with four games left for both teams.

San Francisco (5-7) lost in its first game at its adopted home in Arizona. The 49ers will be based in Glendale for at least the next three weeks after Santa Clara County issued strict new coronavirus protocols that forced the team to find a temporary new home.

It was Allen’s fourth game of the season with at least 300 yards passing and three touchdowns, which set a franchise record. Jim Kelly did it three times in 1991 and Drew Bledsoe three times in 2002.

The Bills had a much more pleasant trip to the desert than three weeks ago, when they lost a 32-30 heartbreaker to the Arizona Cardinals. That was the game when DeAndre Hopkins made a stunning catch over three Buffalo defenders with 2 seconds left for the game-winning score.

San Francisco has had several recent injuries at its slot cornerback position and struggled to cover Beasley, who had a career-high 130 yards receiving on nine catches.

State Farm Stadium — which is home to the division-rival Arizona Cardinals — was dressed up to make the 49ers feel slightly more at home. There were San Francisco banners hanging on the walls along the sidelines and the videoboard showed Niners highlights and flashed messages like “Faithful to the Bay.”

The teams traded goal-line stands in the first quarter.

The Bills opened the game with a 74-yard drive that was stopped at the Niners 1 after Allen’s fourth-down pass fell incomplete. San Francisco responded with a 97-yard drive that ended at the Buffalo 2 when Jeff Wilson Jr. was stuffed for no gain on fourth down.

WASHINGTON 23, PITTSBURGH 17

Pittsburgh’s bid for an unbeaten season is over. Washington’s — yes, Washington’s — quest for an unlikely division title may just be starting.

Alex Smith threw for 296 yards and a touchdown, Dustin Hopkins kicked a tiebreaking 45-yard field goal with 2:04 remaining, and Washington rallied for a 23-17 victory on Monday in one of the biggest surprises of the NFL season.

“We’ve been down for such a long time and we’re trying to rebuild ourselves and build up,” first-year coach Ron Rivera said. “This is something we can build off of.”

The Steelers (11-1) missed a chance to clinch a playoff berth and dropped into a tie with defending Super Bowl champion Kansas City for the best record in the AFC with four weeks remaining. They squandered a 14-point lead.

“It stinks,” Pittsburgh quarterback Ben Roethlisberger said. “Been a while since we lost a game. It’s not a good feeling.”

Still, even after Smith hit Logan Thomas for a 15-yard touchdown pass to tie the game at 17, the Steelers had a chance. They drove into field goal range but rather than have fill-in Matthew Wright — promoted from the practice squad due to an injury to Chris Boswell — attempt a 45-yard field goal into the open end at Heinz, the Steelers went for it. Roethlisberger’s heave to rookie running back Anthony McFarland Jr. fell incomplete and Smith calmly drove Washington 45 yards in nine plays to set up the winning score.