The Kansas City Chiefs are the defending National Football League champions, and in their title defense, they still have the guys who brought them their third Super Bowl last season.

Chief among them are two-time Super Bowl MVP Patrick Mahomes and four-time First Team All-Pro Travis Kelce.

These two have been the most consistent players for coach Andy Reid, even during their struggle in the 2023 regular season.

The 49ers, on the other hand, have Brock Purdy and Christian McCaffrey, who are both in the running for the MVP Award.

Purdy x McCaffrey and Mahomes x Kelce can cancel each other out. It will not be a surprise if they all play splendidly at the Allegiant Stadium on February 11.

The difference maker might be the unheralded and underrated ones-those who are not usually the headliners.

For the Kansas City Chiefs, it is running back Isiah Pacheco.

Chiefs X-Factor: Isiah Pacheco

Pacheco, drafted 251st overall by the Chiefs in 2022, blitzed his way to stardom despite being taken low.

He worked his way to the starting lineup in his rookie season and even had a fantastic performance in the Super Bowl 57 against the Philadelphia Eagles.

In his first season, he completed five touchdowns and posted an average of 48.8 rushing yards.

He underwent surgery before the start of the season, but he is showing no signs of slowing down.

Niners coach Kyle Shanahan is aware of the havoc that Pacheco can bring as one of the best ball carriers in the league this season.

"He is one of the more consistent players in this league," he said.

"Every single run, first run to the last run, to whenever you turn on the clip, cold weather, on the road, at home. He runs extremely hard. He's our type of runner that we like."

Shanahan has every reason to be wary of Pacheco. His team's run defense is not that good.

The 49ers defense allowed Cardinals running back James Conner 6.1 yards per carry while Aaron Jones of the Green Bay Packers recorded 6.0 yards per carry in their Divisional Round showdown.

In the NFC Championship with the Detroit Lions, they trailed most of the time, with RB David Montgomery finishing with 6.2 yards per carry.

The Chiefs will take advantage of that with Pacheco as the focal point. The team started embracing the ground game in 2023.

The 24-year-old posted rush attempt totals of 24, 15, and 24 in the three games he played in the postseason.

He had a subpar outing against the Baltimore Ravens, gaining just 14 yards through the air in just four receptions. However, he did score a touchdown in that game, his third successive game to record at least one TD.

Pacheco recorded more than 100 yards three times in the regular season. The Niners' defense allowed a player to hit that mark just once, and that was in the postseason.

Mahomes and Kelce will put up their usual numbers, but the Niners need to be wary of the ground game if they want to succeed.

Pacheco blitzed his way to stardom. He is running for more.