HENDERSON, Nev. -- Most lists of the key offensive characters ahead of Sunday's Super Bowl showdown between the Kansas City Chiefs and San Francisco 49ers start with Patrick Mahomes, Brock Purdy, Christian McCaffrey, Travis Kelce, Deebo Samuel, Brandon Aiyuk and George Kittle.
It takes a while until you get to Chiefs running back Isiah Pacheco. But the bulldozing running back possesses the potential to tip Sunday's contest on its head.
The 49ers' run defense suddenly became leaky in the postseason. Aaron Jones galloped all over it in the Divisional Round. The Lions mashed the NIners on the ground with David Montgomery and Jahmyr Gibbs in the first half of the NFC Championship Game.
The 49ers ranked third against the rush during the 2023 regular season (allowed 89.7 rushing yards per game). In two postseason games, they've given up 159.0 rush YPG (136 yards to Green Bay, 182 to Detroit), the third-most rushing yards allowed over any two-game playoff span in 49ers history and the first time allowing 250-plus rushing yards over a span of two playoff wins, per NFL Research.
The 69.3 more rushing YPG allowed in the postseason than in the regular season by the Niners is the largest increase in NFL history by a team to reach the Super Bowl (minimum two games).
In steps Pacheco.
"I'm excited to face the Niners," the running back said. "They've got a good front, good defense, guys flying around. That's what it's all about. We love competing for moments like this."
The second-year back has been a sensation, leading the Chiefs with 935 rushing yards, seven rushing touchdowns and 1,179 scrimmage yards in 2023. For much of the campaign, the angry runner had kept the Chiefs' offense afloat when the passing game struggled to find consistent production.
"The coolest thing about being a running back is you get to run as hard as you can, get tackled, get back up as fast as you can, get yelled at by the refs when you threw the ball celebrating," Pacheco said. "It's fun, you've got to love it."
He's always been a violent runner, but the 24-year-old has shown significant improvements in his patience hitting the hole and understanding how to set up blockers, often bluffing defenders into the wrong hole. Those might not sound like impressive traits, but that development has allowed Pacheco to turn what were 2- or 3-yard gains last season into 5- and 6-yarders.
"Just more experienced, understanding technique, fundamentals," offensive coordinator Matt Nagy told NFL.com of Pacheco's improvements this season. "Understanding timing of a pulling guard on a gap play or a trap play. Knowing on a zone read who he's reading, all that stuff. Things happen slower for him, so he can play faster."
Pacheco credits his study time for his Year 2 jump.
"Understanding the hard work put in, understanding the scheme, knowing what coaches want out of you, just putting everything to the side and limiting distractions," he said.
Last year's storyline was how a seventh-round rookie helped energize K.C. on its way to a Super Bowl. Now, that fun runner has become one of the critical cogs of the Chiefs offense.
Coach Andy Reid went so far as to compare Pacheco's running style to that of 49ers great Roger Craig.
"I hate even mentioning this because he was a 49er, but Roger Craig was a violent runner," Reid said when asked if he could compare Pacheco to another back. "He was coming at you with knees and elbows, everything coming at you at one time. They were built kind of the same way and ran with that violence."
Much has been made about Pacheco's "angry" running, but that style allows him to grind on defenses with a relentlessness that wears down opponents.
"Running with a physical style allows you to get up every play, knowing that you didn't look back into the past, and you're just looking forward to the next one," he said. "Putting the pressure on the defense allows you to keep going when you're needed in the fourth quarter."
Where does that style come from?
"It's a determined mindset, knowing when you get out there on the field, you've got to give it your all every play, leaving it all out there allows you to see what you did on the tape," he said. "And if you're going full speed you'll see it on the tape, and knowing that you leave it all out there, if you mess up, it's OK, because you're going as fast as you can."
Nagy noted that Pacheco is fast becoming one of the team's young leaders.
"It's been good to have these young guys coming in here, not just be great players on the football field, but becoming great leaders too," he said. "They don't know it, but they're becoming great leaders, and they're full of energy, which we love."
On Sunday, Pacheco will become the fourth RB in NFL history to start the Super Bowl in each of his first two seasons, joining Duane Thomas (SB V, SB VI), Chuk Foreman (SB VIII, SB IX), and Tony Dorsett (SB XII, SB XIII). None of the previous three won both games.
The former seventh-round pick has 543 scrimmage yards in his playoff career (leads KC and is second in NFL since 2022). He needs 57-plus scrimmage yards on Sunday to become the fifth player (third RB) in NFL history with 600-plus postseason scrimmage yards over his first two seasons, joining Marcus Allen (804), Charlie Brown (653), Ja'Marr Chase (623) and Dorsett (600).
Pacheco has recorded 50-plus rushing yards and one rushing TD in four straight playoff games; only Hall of Famers John Riggins (seven), Terrell Davis (seven), and Franco Harris (two five-game streaks) have longer such playoff streaks since 1970.
On Sunday, he faces a San Francisco defense that knows it needs to be better than the past two weeks, particularly against the run.
The 49ers allowed negative-67 rushing yards over expected in the 2023 regular season (eighth-best in NFL). During the playoffs, they allowed plus-79 RYOE, the worst in the NFL, per Next Gen Stats.
Nagy knows the Niners will be ready for a dose of Pacheco come Sunday.
"You've always got to be able to run the ball in every game because that keeps you ahead of the sticks," the OC said. "We've got to be able to stick to that. They know that, the 49ers know that. In this league, there are great coaches that make adjustments."
If the Niners don't adjust, Super Bowl LVIII will feature more than a few angry highlight runs from Isiah Pacheco.