The New England Patriots held off a Miami Dolphins fightback for a 31-24 win which takes them to 2-0 despite the absence of Tom Brady and now Jimmy Garoppolo.
With the four-time Super Bowl-winning quarterback suspended, his back-up threw for 234 yards and three touchdowns - two of them to Danny Amendola - but left the game with an injury to his throwing shoulder before half-time.
LeGarrette Blount's touchdown run extended the Pats' advantage to a commanding 31-3 in the third quarter as rookie Jacoby Brissett held the fort under centre.
Touchdowns from Kenny Stills, Jordan Cameron and Kenyan Drake set up a tense finish but Duron Harmon intercepted Ryan Tannehill's 'Hail Mary' in the closing seconds to ice the win.
The Pittsburgh Steelers beat the Cincinnati Bengals 24-16 in a repeat of last season's AFC wild card game, and again it finished in controversial circumstances.
After January's Bengals meltdown left Steelers star Antonio Brown concussed by an illegal hit and out of the remainder of the play-offs, this time the dispute was over refereeing decisions.
Trailing by eight with two minutes remaining, the Bengals lost their chance of a comeback when rookie Tyler Boyd was adjudged to have fumbled despite replays showing his knee was down before James Harrison's hit.
Cincinnati were also aggrieved CJ Uzomah's touchdown was not awarded in the third quarter.
Elsewhere in the AFC North, the luckless Cleveland Browns led 20-0 in the first quarter but a blocked extra point, returned by Tavon Young for a rare defensive two-point conversion, sparked a 25-20 comeback win for the Baltimore Ravens featuring two Mike Wallace touchdowns.
Kelvin Benjamin scored twice in the third quarter as last season's Super Bowl runners-up the Carolina Panthers won 46-27 against the San Francisco 49ers.
Carolina's NFC South rivals the New Orleans Saints were beaten 16-13 by the New York Giants after Josh Brown's late field goal.
The Dallas Cowboys edged a tight match against the Washington Redskins in the Giants' NFC East.
With Washington leading 23-20 late in the game, Kirk Cousins was intercepted in the end zone by Barry Church and Dallas drove downfield to win it 27-23 with Alfred Morris' touchdown run.
Marcus Mariota led a fourth-quarter comeback, with touchdown passes to Delanie Walker and Andre Johnson, as the Tennessee Titans beat the Detroit Lions 16-15, while the Houston Texans won 19-12 against the Kansas City Chiefs.
A crowd of more than 91,000 at the Los Angeles Memorial Coliseum were delighted to see the Rams make a winning start on their return to the the city for the first time in nearly 22 years.
Although they have yet to find the end zone since leaving St Louis, Greg Zuerlein's three field goals gave the Rams a 9-3 win over NFC West rivals the Seattle Seahawks, erasing memories of the opening 28-0 loss to San Francisco.
Carson Palmer threw for 308 yards and three touchdowns as the Arizona Cardinals brushed aside the Tampa Bay Buccaneers 40-7, while Justin Hardy snaffled a deflected eight-yard touchdown pass to set up the Atlanta Falcons for a 35-28 win over the Oakland Raiders.
The Jacksonville Jaguars have started 0-2 for the fourth time in five seasons as a result of the 38-14 loss to the San Diego Chargers, for whom Philip Rivers matched his career-high with four touchdown passes, including two to Travis Benjamin.
The New York Jets sunk the Buffalo Bills 37-31, while the Indianapolis Colts are 0-2 for the third year in a row after a 34-20 defeat to the Denver Broncos.
Sam Bradford excelled in Sunday's late game, completing 22 of 30 passes for 286 yards, two touchdowns and no turnovers and leading the Minnesota Vikings to a 17-14 victory over the Green Bay Packers - a result which suited the majority of the 66,000-plus who were watching at the new US Bank Stadium.