1st Quarter: 2nd & 1 at MIN 34 (14:43)

1st Quarter: 1st and 10 at MIN 30 (7:17)

1st Quarter: 2nd and 4 at the SF 28 (4:50)

2nd Quarter: 2nd at 2 at MIN 48 (10:33)

2nd Quarter: 1st and 10 at MIN 43 (1:04)

3rd Quarter: 1st and Goal at the SF 7 (5:26)

4th Quarter: 3rd and 6 at the 50-yard line (2:00)

Bret Rumbeck

Written by: Bret Rumbeck Bret Rumbeck has been writing about the 49ers since 2017 for 49ers Webzone and 49ers Hub. He is a Turlock, CA native, and has worked for two members of the US House of Representatives and one US Senator. When not breaking down game film, Bret spends his time seeking out various forms of heavy metal. Feel free to follow him or direct inquiries to @brumbeck. @brumbeck

In the depths of the cavernous Twitter-takes dungeon, there is a secret room where some hot takes actually became a reality.Somewhere, someone is mining through cat memes, facepalm gifs and arguments over fast-food restaurants looking for that shining moment where he/she correctly predicted how well linebacker Fred Warner 's first NFL season would be.Warner proved to be a diamond in the rough for the 49ers, starting all 16 games his rookie year, playing 1,060 snaps and racking up 124 combined tackles – ranking him 12th in the NFL.One of Warner's best games last season was in Week 1 against the Minnesota Vikings. He led all defenders with 12 combined tackles, had one tackle for a loss, one pass defended and forced a fumble. Warner played every defensive snap, and Pro Football Focus awarded Warner an 88.7 grade for his efforts, his best mark of the season.I reviewed the game film and found seven plays where he made a significant impact.Warner wasted no time making a loud, opening day statement. On the second play of his career, he sniffed out a run and forced Minnesota running back Dalvin Cook to cut against the grain into the arms of unblocked defensive lineman Solomon Thomas In fact, the play foreshadowed a theme that weaved itself throughout the afternoon for Warner and Cook.Defensive coordinator Robert Saleh called a four-man over front, with nose tackle Earl Mitchell aligned in a 0-technique.Saleh also flipped his edge positions, calling for linebacker Mark Nzeocha to play a weakside wide-9 and for Thomas, the strongside end, to play head-up on the Y-receiver.Warner, playing Mike linebacker, shifted himself to the right a few yards just before the snap. I believe Warner's shift altered or confused Minnesota's offensive line; he put himself out of reach from the right guard, and both the center and left guard were occupied.At the snap, Warner moved back to his left and immediately shot the open running lane. Cook wanted no part of Warner and cut back to his left to avoid Warner's wrath.Tight end Kyle Rudolph made a weak block on Thomas, which Thomas quickly broke through to hold Cook to a short 2-yard gain.Warner didn't get credit for a tackle or an assist on the play, but he forced Cook to make the wrong move back into a sea of teammates. It's an example of pure, fundamental football from a player who'd been playing regular season, professional football for fewer than 20 seconds.Minnesota called an outside zone run to the left, while Saleh aligned his four defensive linemen in over front.Defensive tackle Sheldon Day was in a 3-technique to the strongside, while Mitchell was in a zero-shade to the open or weak side of the formation. He also brought cornerback Ahkello Witherspoon down into the box on the closed or strong side of the formation.Warner was over the uncovered A-gap just to his left. Once again, his pre-snap alignment allowed him to be the only unblocked 49er and in position to make a stop.There's more to linebacker than being an aggressive, snarling beast. Great linebackers need to have lateral speed, rage, grace, patience, and brains. And great linebackers are often there to clean up a missed tackle or assignment from a defensive lineman.Linebacker Brock Coyle overshot the play, while Thomas, playing a 6-technique, was unable to control the edge of the line of scrimmage.Warner mirrored Cook's movements and kept Minnesota center Brett Jones from engaging with his body. When Cook finally made a vertical cut, Warner was there to make another tackle.Minnesota ran another zone run with 4:50 left in the first quarter, and again Saleh placed his defensive line in an over front with Witherspoon in the box outside Rudolph.Warner's technique here was a basic linebacker drill run to perfection.Think back to your high school practice when the linebacker coach tossed a few bags on the dusty, dead grass to mimic an offensive line. After choosing a sucker to run the ball, the coach would send the victim back right or left, and then point to a specific gap.The linebacker would read the ball carrier and shoot the gap once he saw the back cut vertically.Warner performed the schoolyard drill on a professional football field, and poor Delvin Cook had no choice but to face Warner one-on-one. Cook lost again.Minnesota called a run to the left against Saleh's 4-3 over front. It wasn't anything special – Cook found a gap in between the center and left guard.The run was away from Warner, so for a moment, it looked like he would not make an impact on the play. As you can see above, it looked as if the 49ers' defense brought down Cook after a few yards.But Warner noticed Cook still running and turned around to make an open field tackle.I don't know if Warner saw or had any idea how poorly Cook was holding the football. Coaching point kids: Always keep four points of contact on the football until you're over the goal line or the referee blows the whistle.As Warner wrapped up Cook, his right hand punched the ball out, and it was recovered by cornerback Richard Sherman Obviously, this was not the first play Warner dropped into coverage. He was one-on-one with wide receiver Adam Thielen at the 6:07 mark in the first quarter. Thielen beat Warner on a what looked like an option route. Warner was already two-steps behind when Thielen cut toward the sidelines.Warner got his revenge on Thielen in the fourth quarter when he jumped into Cousins' throwing lane to disrupt a short vertical route. I couldn't tell if Warner tipped the ball or Cousins threw too far behind Thielen, but Thielen dropped the pass, and Minnesota went three-and-out.With just over a minute left in the first half, Minnesota tried to get a big play from a short route. The trips side of the formation ran patterns to clear the 49er defensive backs and linebackers, while wide receiver Stefon Diggs ran a short drive route from the right side of the formation.One would think that Diggs running full speed into the open field would have yielded a big play for Minnesota. But it failed for two reasons.First, Cousins held the ball for far too long. Maybe he keyed on the dig route, but Warner appears to be dropping into that throwing lane. With Warner shutting down the first read, Cousins should have immediately lowered his eyes to Diggs to allow him to work in the open space.Maybe Cousins needed a bigger window to hit Diggs in stride, or perhaps Cousins isn't a bright quarterback.Warner was the second reason the play failed.Once Warner hit the top of his drop, he figured out what the Vikings were doing with the play. Cousins had yet to throw, but Warner – about seven yards away from Diggs – was ready to shut down any hopes of big yardage.Warner closed the gap immediately and held Diggs to a paltry three-yard gain.Here's another angle of the play just as Warner began to break on the drive route. The combination of Cousins' hesitation and Warner's speed helped tremendously.Oddly, Minnesota called a nearly identical play with 12-seconds left in the half but sent wide receiver Laquon Treadwell on the short drive pattern. Cousins didn't learn from the first play, held on to the ball too long, and again Warner held Minnesota to a 2-yard gain.I'm hopeful with the additions of Kwon Alexander Dee Ford , and Nick Bosa , we'll see the 49ers' defense exploit the dumb mistakes from subpar quarterbacks.This was the fourth battle between Warner and Cook, with Warner once again emerging as the clear victor.With center Brett Jones immediately going to the second level to block Coyle, Warner moved to his right to shoot the open running gap.Warner hit the running lane at full steam just as Cook was getting the ball from Cousins. Cook had two choices: lower his shoulder and take on Warner, or curl up and die.Cook's fear of Warner was higher than the glory of an opening day touchdown, so he curled up and took a 1-yard gain.I don't know if Warner knew he had no help behind him, but it was a critical tackle at that moment. Unfortunately, Minnesota scored a minute later.Warner was great in coverage all afternoon. He was targeted five times, allowing three catches for 19 yards. His instantaneous tackles on both of Minnesota's drive routes were outstanding, but his last play in coverage stood out a bit more.Immediately at the snap, Warner turned his head to the right. Tight end Kyle Rudolph was flexed out from the end of the line of scrimmage by about six yards.Cousins looked off to his left, with a hope to find Thielen on a 'Colorado' route. However, Cousins wasn't patient enough and brought his eyes to Rudolph's under route.Maybe Rudolph was open or beat the inside linebacker during practice or a preseason game on the under route; otherwise, I can't figure out what Cousins was thinking on the play. Either he didn't see Warner behind Rudolph, or he thought Rudolph would beat Warner to the spot.Somehow, Warner went from a stationary position to in-stride with Rudolph. By the time the ball left Cousins' hand, Warner was even with Rudolph. It appeared that Warner's fingers were enough to break Rudolph's concentration, and the ball fell to the artificial turf. Seconds later, Rudolph begged for a pass interference call from the official.The Alexander-Warner duo could be one of the best linebacker corps in pro football this fall, and I am looking forward to seeing if Warner can improve on an impressive rookie year.Photos courtesy ofAll stats courtesy ofunless noted.