As the National Football League season passed the halfway point on Sunday, only one thing remained clear. Nothing this season can be taken for granted.
The NFL prides itself on being an evenly-balanced competition and the first nine weeks of the season have lived up to that billing with a series of unpredictable results.
Sunday was no different. The Kansas City Chiefs (9-0) continued to defy the odds, beating the Buffalo Bills (3-6) 23-13 to remain as the NFL's only undefeated team.
The New York Jets (5-4), as up-and-down a team as any, beat the high-flying New Orleans Saints (6-2) 26-20, a week after they suffered a 40-point thrashing to the Cincinnati Bengals (6-3).
The Carolina Panthers (5-3), another team who have torn up the script, completed a 34-10 thumping of the Atlanta Falcons, who made the NFC Championship last season but have fallen to 2-6 this campaign.
And the New England Patriots (7-2) and the Philadelphia Eagles (4-5) both romped to huge wins after the Seattle Seahawks (8-1) survived a major scare against the winless Tampa Bay Buccaneers (0-8).
The Chiefs finished tied for the league's worst record (2-14) a year ago but continue their incredible run under new coach Andy Reid, overturning 10-3 halftime deficit to win away from home after Sean Smith returned an interception 100 yards for a touchdown.
The Jets have been on an unusual sequence this season, alternating between wins and losses each week.
This week they were due to win but had to work against a Saints that got 382 yards and two touchdown passes from quarterback Drew Brees at Metlife Stadium.
Jets quarterback Geno Smith threw for just 115 yards but he rushed for a three-yard touchdown that gave his team the lead while Nick Folk kicked four field goals to maintain his perfect record this season.
"We knew it was going to be tough. We didn't know how we'd win. All I know is I have a team that believes and will fight all the way," said Jets head coach Rex Ryan, whose brother Rob is the defensive co-ordinator with the Saints.
"All season we've won one, lost one, won one, lost one and we've got the bye next week, so we're going to lose that one."
The Panthers made four wins on the trot, picking off three interceptions. Cam Newton threw for one touchdown and ran in one himself in Charlotte.
A week after throwing away victory against the Detroit Lions, the Dallas Cowboys (5-4) secured a last-minute, 27-23 win against the struggling Minnesota Vikings (1-7) in Texas.
Dallas quarterback Tony Romo threw for 337 yards and two touchdowns, including the game-winner to Dwayne Harris with just 35 seconds left on the clock.
The Tennessee Titans (4-4) ended a three-game losing streak with a 28-21 victory away to the St. Louis Rams (3-6) with running back Chris Johnson, who rushed for 150 yards, scoring the winning touchdown less than three minutes from the end.
The Washington Redskins (3-5) regained their composure after blowing a 10-point lead in the last quarter to beat San Diego Chargers (4-4) 30-24 in overtime with fullback Darrel Young securing the win with a four-yard touchdown run.
New England quarterback Tom Brady had a field day in his team's 55-31 win over the Pittsburgh Steelers (2-6).
Brady completed 23-for-33 passes for 432 yards and four touchdowns to move into sixth place on the NFL's all-time completion list and seventh in passing yards.
Philadelphia quarterback Nick Foles threw an NFL-record-tying seven touchdown passes in the Eagles' 49-20 victory over the Oakland Raiders (3-5).
Foles became just the seventh quarterback to throw seven touchdown passes in an NFL game. The most recent was Peyton Manning, earlier this season.
The Seahawks, one of the favourites to win the Super Bowl, overcame a 21-0 deficit against the Buccaneers to win 27-24 in overtime.
The reigning Super Bowl champions, the Baltimore Ravens (3-5), lost 24-18 against the Cleveland Browns (4-5).