The Green Bay Packers emerged from the first quarter of the 2019 season with a 3-1 record, using wins over the Chicago Bears, Minnesota Vikings and Denver Broncos to power an encouraging start to the Matt LaFleur era.

Now, the Packers must build on what’s been built during the first four games and fight through a tough stretch of games over the next two months.

Here’s what we’ve learned about LaFleur’s team during the first four weeks:

Smiths are legit: The Packers’ new pass-rushing duo has been better than anyone could have reasonably imagined. Za’Darius and Preston Smith immediately assumed leadership roles on defense while simultaneously adding the right combination of size, versatility and disruptive abilities to the Packers’ front. Through four games, the pair has 7.5 sacks and 15 quarterback hits. Both are on pace to go over 10 sacks. The Packers have to be overwhelmingly pleased with their investment on the edge. One thing to monitor: Both Za’Darius and Preston have played over 80 percent of the defense’s total snaps. More might be required from Kyler Fackrell and rookie Rashan Gary to keep the Smiths healthy and fresh all season.

Offense working through growing pains: It’s still difficult to determine where the Packers are at on offense. They’ve played four great defensive fronts and haven’t been able to consistently run the football, a core aspect of LaFleur’s plan. The passing game has been hit or miss, although there are signs that LaFleur and Aaron Rodgers are starting to get on the same page. It was always reasonable to expect this group to start slow but gradually gain momentum, especially as the offense identified strengths and established an overall identity. There’s been legitimate improvement each week. Time will tell if there’s enough talent at receiver and tight end to gain consistency, the hallmark of all great offenses.

Alexander is a star: Predicting a second-year jump from cornerback Jaire Alexander was easy, but his ascension from promising rookie to dominant sophomore has been rapid and obvious the first four games. He’s provided Mike Pettine a legitimate shutdown cornerback, with the confidence and ability to match up against any receiver on an island but also the instincts and playmaking skills to attack in zone coverages. After four weeks, Alexander has six pass breakups and several other forced incompletions. His takeaway against the Broncos was a perfect example of a star creating a game-changing play. He’s already making a strong case for himself as one of the NFL’s 5-10 best cornerbacks.

Leaky run defense: The Packers are allowing 142 rushing yards a game, including two individual games allowing over 175 (198 vs. Vikings, 176 vs. Eagles). It’s possible the run defense is going to be a major issue all season. Not only are the Packers severely lacking in inside linebacker talent, but defensive coordinator Mike Pettine simply doesn’t prioritize stopping the run. He’d rather play light and have the right personnel to contain the passing game. The loss of Raven Greene looms large. Can Oren Burks return and balance out the back seven? The second-year linebacker is looking more and more important.

Impact rookies: Top pick Rashan Gary will need time to develop into a difference-maker, but GM Brian Gutekunst might have hit home runs with safety Darnell Savage and offensive lineman Elgton Jenkins. Savage has provided game-changing and window-shrinking speed, with some flashes of Nick Collins-like playmaking ability in the passing game. It probably won’t be surprising if he makes multiple Pro Bowls during his rookie contract. His talent is abundant. On offense, Jenkins has played in three games and started two games at left guard. He has the foundational skillset to be the Packers’ best guard since T.J. Lang. Against both the Broncos and Eagles, Jenkins displayed the combination of toughness, movement ability and pass protection skills that could make him a top-level starter in the NFL.

Talented secondary: Most rightly assumed the secondary would be significantly improved, but the pieces at cornerback and safety have fit together exceedingly well to start 2019. Alexander has set a Pro Bowl trajectory as the team’s undisputed No. 1 cornerback, Kevin King has flashed disruptive ability in the right matchups, Adrian Amos and Tramon Williams are both as reliable and consistent as ever and Savage has tied everything together with speed and instincts. If this group stays healthy, it could be one of the league’s best. There are major questions behind them, however. Can Will Redmond really play the third safety role all year? And will Josh Jackson finally emerge as someone Mike Pettine can rely on? The answers to those questions may eventually determine the overall quality of the rebuilt secondary.

Tight end troubles: Jimmy Graham has already matched his touchdown total from last season, and Marcedes Lewis and Robert Tonyan have each topped their respective reception totals from 2018. Still, there’s reason to be concerned about the tight end position. Graham remains an odd fit in LaFleur’s offense, Lewis is no longer a consistently great run blocker and Tonyan hasn’t been given many opportunities. It’s possible rookie Jace Sternberger will come off IR later in the season and provide something more in the passing game, but that’s unlikely. The Packers have played a lot of snaps with multiple tight ends on the field, but the position has been a net negative after four games.

Still struggling special teams: The Packers were good on special teams in Week 1 but have been struggling ever since. The return game can’t get going and the coverage units have been disappointing. Each of the last two weeks, the Packers allowed a return of 60 or more yards. Kicker Mason Crosby also shanked a kickoff out of bounds, setting up another short field, and missed a kick against the Broncos. The star of the show has been second-year punter JK Scott, who has boomed punts all season. He’s getting terrific distance and hangtime. Can he keep hitting bombs once the weather turns? He’s been a field-flipping weapon the first four games.

Bulaga is still elite: The Packers right tackle exited Thursday night’s loss to the Eagles with a shoulder injury, but he was enjoying a standout start to his 2019 season through the first 3.5 games. Bulaga went head-to-head with Khalil Mack, Leonard Floyd, Danielle Hunter, Bradley Chubb and Brandon Graham and either won or held serve in each matchup. When healthy, Bulaga is one of the NFL’s elite pass blockers, and the Packers were absolutely right to bring him back for 2019. Injury concerns linger, however.