The Detroit Lions suffered their first defeat of the National Football League season on Sunday, their 25-19 loss to the San Francisco 49ers leaving the Green Bay Packers as the only unbeaten team after six weeks of play.
Another early season pace-setter, the Buffalo Bills, also came crashing down to earth with a 27-24 loss to the New York Giants while the Indianapolis Colts, still without injured quarterback Peyton Manning, slumped to 0-6 following a 27-17 defeat at Cincinnati.
The 49ers improved to a 5-1 record after an impressive comeback victory at Detroit.
Alex Smith found Delainie Walker with a six-yard touchdown pass in the fourth quarter to put San Francisco ahead with 1:51 left on the clock.
The Lions were unable to find a first down on the next possession against some outstanding defense from the 49ers before a 37-yard David Akers field goal made sure of a 25-19 win for San Francisco.
The win was a big statement from the 49ers -- as well as becoming the first team to beat the Lions, it was their third straight win on the road.
To rub salt into the wound for Detroit, their first loss meant they gave up top spot in the NFC North -- to defending Super Bowl champions, the Green Bay Packers.
The Packers easily dealt with the winless St. Louis Rams, quarterback Aaron Rodgers throwing three touchdowns in the 24-3 victory at Lambeau Field.
Rodgers threw for 310 yards and the highlight of yet another masterclass from their quarterback was a career-long 93-yard touchdown pass to Jordy Nelson.
The Bills (4-2) have been the surprise package of the season so far but their limitations were on show at the New Meadowlands where the Giants' Ahmad Bradshaw ran for three touchdowns and 104 yards for New York.
The scores were tied at 24-24 when Bills quarterback Ryan Fitzpatrick was intercepted, for the second time, by Corey Webster. Giants quarterback Eli Manning then led a drive down the field which ended with Lawrence Tynes's 23-yard game-winning field goal.
The Colts' awful season continued in painful fashion -- after a potential score-leveling Indianapolis field goal attempt was blocked, Carlos Dunlap grabbed a fumble and returned it 35 yards for a touchdown to secure the victory for the Bengals.
Rashard Mendenhall ran for 146 yards and a touchdown as the Pittsburgh Steelers (4-2) ran out 17-13 winners at the Jacksonville Jaguars (1-5).
The Philadelphia Eagles earned a much-needed win with a 20-13 victory at Washington, although they were helped generously by Redskins quarterback Rex Grossman who threw four interceptions before he was benched.