The Patriots’ high-flying passing game hogged most of the spotlight during the team’s run to 13 wins and the no. 1 seed in the AFC this year. The 40-year-old Tom Brady defied Father Time and is (most likely) about to win his third MVP award. Tight end Rob Gronkowski confounded defenses all year long, speedster Brandin Cooks provided the over-the-top threat, and both went over 1,000 yards receiving while combining for 15 touchdowns. But while that troika certainly deserves plenty of the credit for the team’s offensive success, New England added another important piece to its winning formula in the second half of the year: a rushing attack.

Dion Lewis emerged as one of the most reliable playmakers in the league over the back half of the season, carving out his role as New England’s backfield leader. Lewis has quietly become the best, most complete running back that Brady’s worked with in years—and he could be the X factor for a long Patriots playoff run.

It was a long road to the top of the Patriots’ depth chart for the 27-year-old former Pitt star, particularly in the unpredictable New England backfield, where Bill Belichick often cycles through starters on a game-to-game basis and frequently sends players to the bench for egregious mistakes or fumbles. Three years ago last week, New England signed the former Eagles, Browns, and Colts running back to a futures contract despite the fact he hadn’t played in a game in two full years. Lewis missed all of 2013 with a broken fibula, was out of the league in 2014, and was a relative unknown when he made the team’s active roster at the start of 2015, but he played well that year, racking up 622 yards from scrimmage and four touchdowns (two on the ground, two through the air) before an ACL tear in early November cut his season short. The 5-foot-9, 195-pound back returned to the field in Week 11 of 2016, and played behind LeGarrette Blount in a pass-catching, rotational role.

Coming into this season, it wasn’t clear where Lewis would fit in; the Patriots had moved on from Blount, who’d logged 299 carries and scored 18 touchdowns as the bell-cow runner in 2016, and added free agents Rex Burkhead and Mike Gillislee to a group that included Lewis and Super Bowl hero James White. Gillislee and White started the year atop the pecking order, but Lewis gradually got more reps and, with a little help from a Gillislee fumble in the team’s Week 6 win over the Jets, leapfrogged both guys in front of him. Lewis never looked back, holding on to the de facto starter’s job the rest of the year en route to career highs in carries (180), yards (896), and touchdowns (six), with 32 catches for 214 yards and three scores as a pass catcher out of the backfield. Oh, and he added 23 kick returns for 570 yards and a touchdown, just for good measure.

Lewis is no longer just a pass-catching satellite back to be utilized in advantageous situations—he’s become a between-the-tackles sustainer that Brady, Belichick, and offensive coordinator Josh McDaniels leaned on more and more as the year went on.

Dion Lewis getting stronger as the year has gone on. Not a small back just short. — Michael Lombardi (@mlombardiNFL) December 31, 2017

The uptick in Lewis’s usage coincides with the improvement in the Patriots’ run game late in the season. New England tied for the league high in rushing touchdowns over the final six weeks, a stretch in which the Patriots ranked second in rush yards (829) and third in yards per carry (4.66). In that final six-week spell, Lewis ranked second in the NFL in rushing yards—behind only Todd Gurley—and showcased his big-play ability, logging eight rushes over 15 yards, second only to Marshawn Lynch in that period.

Because he didn’t take over lead-back duties until midseason, Lewis’s volume stats don’t stand out, but the efficiency numbers paint a picture of one of the best backs in the NFL. He forced 49 missed tackles, and led all qualifying backs (minimum 50 percent of snaps played) with an elusive rating of 73.2, per Pro Football Focus. He ranked third among those players in yards after contact per carry (3.17). He also registered a perfect pass-blocking efficiency grade per PFF, giving up zero pressures or sacks on 35 pass-blocking snaps. He finished the year with zero drops on 32 catchable targets, didn’t fumble the ball a single time on 212 touches, and ranked first among running backs in Football Outsiders DYAR (total value) and second in DVOA (value per play). He became one of just five players in the Super Bowl era (joining Jamaal Charles, Maurice Jones-Drew, Terry Metcalf, and Gale Sayers) with 800-plus yards rushing, 150-plus yards receiving, 500-plus yards on kickoff returns, and at least one rushing, receiving, and kickoff return touchdown in a single season.

The first thing that stands out in Lewis’s game is his suddenness as a runner. He’s lightning fast from stop to start, and he’s figuratively broken plenty of defenders’ ankles this year with cut-on-a-dime jukes and lateral cuts. That ability was on full display early in the Patriots’ matchup with the Jets in Week 17, when he first bounced to his right to get to the outside before cutting it back upfield, leaving corner Juston Burris grasping at a cloud of dust.

Against the Bills in Week 16, Lewis bounced another run to the outside, first dispatching linebacker Lorenzo Alexander to the ground with a slick stiff-arm before juking corner Lafayette Pitts off his feet to gain a few more yards.

Lewis administered an even more impressive stiff-arm in the team’s Week 13 matchup with Buffalo. After cutting upfield, breaking a pair of tackle attempts, and getting down the sideline, he threw safety Jordan Poyer out of the way with a Beast Mode–esque hand to the face, picking up another 15 yards before being pushed out of bounds.

Lewis is most dangerous on the outside, in space—he finished third in the league in yards per carry (5.1) on outside runs—but he’s got no problem running “into the briar patch” between the tackles, too. He showed that in that Week 13 game, busting through a pair of tackles before spinning to pick up an extra couple of hard yards.

Against the Dolphins in Week 12, he had a pair of impressive runs right up the gut. On the first, he hurdled a defender in his path before hitting the gas and tearing through a would-be arm tackle to pick up big yardage.

On the second, he shed another arm tackle before making his way upfield, spinning away from contact before going airborne the final 2 or 3 yards.

Lewis runs with surprising power for a player his size, where his balance through contact and compact stature makes him a tough player to wrap up. There are plays, too, where his (lack of) height actually comes in handy. Against the Bills, you can see Buffalo safety Poyer lose sight of the diminutive ball carrier (hell, the overhead camera loses sight of him for a second, too), and as Poyer over-pursues to his left, Lewis cuts the ball back the other direction and dives in for the score.

Against the Dolphins, Lewis’s size disadvantage again became a blessing; watch linebacker Kiko Alonso lose the Patriots back in the wash, and by the time Lewis breaks free, Alonso is out of position.

Lewis consistently displays incredible—dare I say, even Le’Veon Bell–like—patience behind the line. He lets his blocks set up, chooses his running lanes, and after lulling the defense to sleep, explodes downfield like he was shot out of a cannon. Here are a few examples:

I mean, look at this:

Of course, the Titans field one of the most stout run-defending fronts in the league, which could mean tough sledding for Lewis and the Patriots run game. Tennessee limited Kareem Hunt to just 42 yards on 11 carries last week, and the Titans aren’t going to give New England much room to operate on the ground. But even if Lewis can’t get much production going on the ground, the reliable pass catcher can still create plenty of matchup problems for a defense. He was no slouch in the passing game this year, where he ranked ninth in receiving DVOA among running backs and 12th in DYAR. Whether he’s taking a handoff and running it between the tackles or taking an outlet pass on the wing, his elusiveness shows up.

The Patriots offense is always going to center around Brady’s arm—with Gronk running up the seam or posting up in the red zone and Cooks running fly patterns downfield. But Lewis’s versatility—his ability to pick up chunk yardage on the ground or make plays through the air—makes New England a team for which it’s almost impossible to game plan. The 27-year-old back is elusive, explosive, and savvy, and is equally as dangerous running up the gut, cutting the ball outside, or catching a pass out of the backfield. How do you line up against a team that can beat you through the air with its future Hall of Fame quarterback and demoralize you with explosive runs on the ground? Which personnel do you employ? Who do you try to take away? There’s no clear answer, and with the way that Lewis has run the ball the last couple of months, it’s a riddle opposing defenses are going to struggle to answer this postseason.