The previously unbeaten Buffalo Bills and Philadelphia Eagles both slumped to upset losses in the NFL on Sunday as the injury-hit Baltimore Ravens suffered a humiliating blowout.

The Bills — regarded by many as favorites for this season's Super Bowl — were stunned 23-20 by the resurgent New England Patriots in a pulsating duel at Buffalo's Highmark Stadium.

Patriots quarterback Drake Maye showed composure beyond his 23 years to engineer the game-winning drive in the final minute of the fourth quarter, setting up Andy Borregales' 52-yard field goal.