Eight teams are 2-0 to start the 2016 NFL season, and only one Week 3 game features a matchup of two unbeatens. The Pittsburgh Steelers visit the Philadelphia Eagles on Sunday afternoon in what’s unexpectedly become one of the biggest games on the upcoming schedule.

It’s not surprising that Pittsburgh has gotten off to a hot start, beginning the season as the top threat to the New England Patriots in the AFC. The Philadelphia Eagles were supposed to have a rebuilding season, thrusting rookie Carson Wentz into the starting quarterback position just a week before the year’s first NFL Sunday. But he’s been impressive, along with Philadelphia’s defense, potentially posing a challenge to one of the league’s top Super Bowl contenders.

Wentz looked nothing like a first-year player when he led the Eagles to a 29-14 win against the Chicago Bears on “Monday Night Football.” Proving that his performance in the season opener against the Cleveland Browns was no fluke, Wentz completed 61.8 percent of his passes for a touchdown and no interceptions, easily winning the first road game of his career. He has a 94.1 passer rating, and he’s one of just seven quarterbacks to make two starts this year without throwing a pick.

The Steelers opened as 5.5-point favorites at Las Vegas and online sportsbooks, via OddsShark, but the betting line quickly moved to 3.5 points on Tuesday. Wentz appears to be the real deal, making the Eagles a legitimate upset threat in Week 3.

While Wentz wasn’t expected to make this kind of impact so quickly, Ben Roethlisberger is putting up his usual impressive numbers. He’s the only quarterback with six touchdown passes, throwing for at least 259 yards in each game. Even with No.1 wide receiver Antonio Brown being limited to 39 yards in Pittsburgh’s Week 2 win against the Cincinnati Bengals, Roethlisberger connected with Sammie Coates for 97 yards in a 24-16 victory.

Perhaps most important to the Steelers’ success has been the play of running back DeAngelo Williams. In place of the suspended Le’Veon Bell, Williams easily leads the league with 237 yards on the ground. He’s totaled 303 yards of total offense and three touchdowns, making the case to be recognized as the best backup at any position in the NFL.

Roethlisberger, Williams and the Steelers have won two games against one of the NFL’s toughest schedules. They had a comfortable eight-point win against the Bengals, who have made five straight playoff appearances and should be back in the postseason this year. The Washington Redskins might not be as good as they were when they won the NFC East in 2015, but Pittsburgh’s 38-16 victory against the defending division champs in Week 1 was certainly impressive.

Wentz and Philadelphia still haven’t beaten a formidable opponent. Two straight double-digit wins mean that the Eagles are better than most experts thought, but they might have beaten the two worst teams in the NFL. Facing Pittsburgh will be an entirely different challenge.

A year after Kirk Cousins set a record for completion percentage at home in a single season, the Steelers kept the Redskins' quarterback out of the end zone and intercepted him twice. Andy Dalton led the Bengals on just one touchdown drive against Pittsburgh, and his 6.78 yards per attempt were the fewest in his last six games. Only the Green Bay Packers have allowed fewer rushing yards than the Steelers.

Philadelphia’s defense is improved from last year, especially with their ability to pressure the quarterback. Roethlisberger has already thrown three interceptions this season, and the Eagles could remain competitive on Sunday by forcing the quarterback into a few turnovers. Their best chance is to keep the game below the over/under of 46 points.

But Philadelphia remains vulnerable against the run after allowing more yards on the ground than any team last year. With an explosive offense and one of the league’s best all-around teams, the Steelers should be able to pull out a hard-fought victory.

Prediction: Pittsburgh over Philadelphia, 27-20