The Dallas Cowboys are 1-0 to start the season after beating the New York Giants 19-3. Let's take a look at what we've learned about the Cowboys after one week of NFL action:

1) Much-improved defense: Dallas held New York to just two first downs in the first half, flustering an Odell Beckham-less Giants team all night. New York finished the game with a humbling three points and 233 yards of total offense. The Cowboys front seven bottled up the run game any time the Giants put it on the ground, and limited New York to 35 yards rushing.

As a result, Eli Manning was forced to air it out. Playing from behind and without Beckham, the Giants had no chance against a Dallas team determined to avenge its two losses from a season ago. DeMarcus Lawrence applied pressure off the edge seemingly all game while Sean Lee and Jaylon Smith shored up the middle of the field. If the Cowboys defense plays like this all year, they will be a nightmare for any team and a tough out.

2) Dak has matured: His numbers weren't eye-popping – 24-of-39 for 268 yards and one touchdown, but Prescott showed he has somehow managed to improve on his record-setting rookie campaign.

On their first drive of the game, Dallas handed Dak the reins, letting him run the offense without a huddle and make audibles at the line of scrimmage. In stark contrast to last season when Jason Garrett and Scott Linehan just wanted to simplify things, Prescott seems to have much more control over the direction of the offense.

And why not? Through 18 career NFL games, Prescott has still only thrown five interceptions if you count the pick from last year's playoff game against Green Bay. He simply just doesn't turn it over. Now that he's beaten the Giants, he's also beaten every team he's played at least once.

3) What offensive line question marks? For all the talk in the offseason about the departure of Ronald Leary and Doug Free, you'd be hard-pressed to say the Cowboys missed them Sunday night. With Chaz Green and La'el Collins starting in their places, Dallas still racked up 392 yards of total offense, including a 104-yard performance from Ezekiel Elliott.

Dak Prescott was only sacked once, and had plenty of time to make his reads and throw down the field. Against one of the best defensive lines in football – and a team that manhandled them up front last year – the Cowboys offensive line had no trouble.

4) New-look secondary looked good: The Cowboys ranked 26th in the NFL last season against the pass, allowing opponents to gain an average of 260.4 yards per game through the air. After losing Barry Church, J.J. Wilcox, Morris Claiborne and Brandon Carr in free agency, Dallas turned to the draft and free agency to rebuild the back end of its defense.

Sunday against New York, the Cowboys gave up 198 yards passing, intercepted Manning once, and held the Giants to just 4.8 yards per pass. Even with Orlando Scandrick leaving the game with an injury, Dallas' secondary never got burned for the big play and kept everything in front of them.

5) Barring injuries, this team could contend for a Super Bowl: Okay, okay, hear me out. I know its just one game, but the Cowboys already knocked off the team that beat them twice last year, and a team many projected to win the NFC East. Few expected Dallas' defense to play as well as they did.

With a juggernaut offense that dominates time of possession, the Cowboys should be considered legitimate contenders if they keep up this level of play all season. Dallas won the time of possession battle Sunday 34:14 to 25:16, giving their defense plenty of time to rest on the sidelines.

Obviously it's September and there's plenty of season left, but the Cowboys made a statement with an emphatic victory over a rival in their season opener.

What were your takeaways from Week 1 of the NFL season? Share 'em with Reece on Twitter: @ReeceWaddell15.