Both San Francisco and Kansas City have high-powered offenses but their defenses – the 49ers led by Nick Bosa, left, and the Chiefs led by Chris Jones, right – will likely determine the Super Bowl. Associated Press

LAS VEGAS — The Chiefs go as far as Patrick Mahomes takes them. The 49ers have Christian McCaffrey, Deebo Samuel, George Kittle and a star-studded group surrounding Brock Purdy.

This Super Bowl will come down to the other side of the ball.

Defense wins the Vince Lombardi Trophy on Sunday.

Kansas City is seeking to become the NFL’s first repeat champion in 19 years. San Francisco is aiming for a record-tying sixth Super Bowl title.

Mahomes, Travis Kelce and Coach Andy Reid get most of the attention on the Chiefs (14-6), but defensive coordinator Steve Spagnuolo’s unit deserves plenty of credit for carrying the team during various points of the season when the offense was inconsistent and out of sync.

All-Pros Chris Jones and Trent McDuffie along with George Karlaftis, L’Jarius Sneed and others stepped up, giving the Chiefs their best defense of Mahomes’ era.

They’ll need to do it for one more game against a versatile, dynamic offense.

The 49ers (14-5) also have a formidable defense led by Nick Bosa, All-Pro Fred Warner, Javon Hargrave and Charvarius Ward. They’ve struggled in the postseason, especially making third-down stops.

They have to be better against Mahomes and the Chiefs to have a shot to win.

WHEN THE 49ERS HAVE THE BALL

Christian McCaffrey leads San Francisco’s third-ranked rushing attack. Abbie Parr/Associated Press

The 49ers had the league’s third-ranked rushing attack behind McCaffrey and fourth-ranked passing offense behind Purdy. The Chiefs gave up the second-fewest points (17.3), were fourth against the pass and 18th against the run.

McCaffrey, tight end Kittle, left tackle Trent Williams and fullback Kyle Juszczyk were All-Pros. Brandon Aiyuk was a second-team All-Pro. Samuel is a versatile, do-everything player.

The 49ers have plenty of weapons, and Coach Kyle Shanahan is known for finding innovative ways to use them and keep defenses off balance. He’s facing a master tactician in Spagnuolo.

It’ll be a chess match.

Spagnuolo has a penchant for blitzing. Purdy excelled against it.

The 49ers have to block Jones, who can be a game-wrecker. McDuffie is a shutdown slot cornerback and Sneed allowed only one receiver all season to have more than 50 yards receiving in a game so Purdy has a tough task.

He led the NFL with a 113.0 passer rating on 4,280 yards, 31 TDs, 11 picks and a 69.4% completion rate. McCaffrey led the NFL with 1,459 yards rushing and had 14 rushing TDs for San Francisco. He also had 564 yards receiving for seven scores.

Kittle had 65 catches for 1,020 yards and six TDs. Aiyuk led the way with 75 receptions for 1,342 yards and seven scores. Samuel had 1,117 yards from scrimmage.

A wild card for San Francisco’s offense is Purdy’s surprising mobility. His scrambling was a major factor as he led comeback wins against the Lions and Packers in the playoffs.

The Chiefs shut down two-time MVP Lamar Jackson, the best running QB in the NFL, so they’ll be ready for Purdy.

WHEN THE CHIEFS HAVE THE BALL

Chiefs tight end Travis Kelce has 23 catches for 262 yards and three touchdowns in three playoff games this season. Mike Roemer/Associated Press

The Chiefs had the league’s sixth-ranked passing offense behind Mahomes and 19th-ranked rushing attack. The 49ers were 14th against the pass and third against the run, but they have allowed 13 of 25 third-down conversions in the playoffs.

Mahomes is a brilliant playmaker who finds unique ways to make big plays when it seems nothing is available. The two-time NFL and Super Bowl MVP threw for 4,183 yards with 27 touchdowns, a career-high 14 interceptions and career-low 92.6 passer rating. His receivers dropped 44 passes, the most in the league.

The Chiefs’ offense runs through Mahomes and Kelce. Without a deep threat – Tyreek Hill was traded to Miami two years ago — Reid has turned the passing offense into a shorter, carve-up attack.

Rashee Rice has the ability to turn screens into big plays and veteran Marquez Valdes-Scantling has averaged 21.6 yards per catch in the playoffs.

Kelce had 93 catches for 984 yards and five TDs in the regular season and he has taken his game to another level in the playoffs, with 23 catches for 262 yards and three scores in three games. Rice had 79 receptions for 938 yards and seven TDs in the regular season.

The Chiefs have to use running back Isiah Pacheco to balance the offense. He ran for 935 yards and seven TDs in the regular season, and he has 254 yards and three scores in the playoffs.

Reid is one of the NFL’s most creative coaches, and he’s willing to add new wrinkles in the biggest games. Kansas City again won’t have All-Pro left guard Joe Thuney and the offensive line has a big challenge protecting Mahomes from Bosa, Hargrave and the rest of San Francisco’s pass rush.

Warner and Dre Greenlaw can control of the middle of the field and limit some of Kelce’s opportunities, forcing the Chiefs to attack outside.

Mahomes can always make plays with his legs. He scrambled for 26 first downs in the regular season. Playing on an injured ankle in last year’s Super Bowl, he had a big scramble on Kansas City’s go-ahead drive in a comeback win over Philadelphia.

If the 49ers bring the heat and turn up the pressure like Tampa Bay did against Mahomes in the Super Bowl three years ago, that could be trouble for the Chiefs.

SPECIAL TEAMS

Niners rookie kicker Jake Moody was 21 of 25 on field goals in the regular season, but he’s looked shaky in the playoffs, with two misses in five tries. His longest field goal was 57 yards.

Chiefs kicker Harrison Butker made 33 of 35 field goals in the regular season, including all five from beyond 50 yards. He hasn’t missed in the playoffs, making seven field goals and seven extra points. Butker’s 27-yard field goal with 8 seconds left gave the Chiefs a 38-35 win over Philadelphia in last season’s Super Bowl.

San Francisco punter Mitch Wishnowsky had a 42.7-yard net average. Kansas City’s Tommy Townsend had a 41.9-yard net average.

The Chiefs use Mecole Hardman and Richie James for returns. Hardman had the longest punt return at 50 yards and James had the longest kick return at 31.

The 49ers will sometimes use Samuel on kick returns, with Ray-Ray McCloud getting most of the returns on punts and kicks.

COACHING

Shanahan is 8-3 in the playoffs and 0-2 in Super Bowls, including one as an assistant. His 49ers blew a lead against the Chiefs in this game four years ago and he was offensive coordinator for Atlanta when the Falcons blew a 28-3 lead against Tom Brady and the Patriots in Super Bowl 51.

Reid is a likely future Hall of Famer. He already has two Super Bowl rings and is the winningest coach in the history of the Chiefs and Eagles.

INTANGIBLES

The 49ers initially were 2 1/2 favorites, but the line dropped to 1 1/2 on Saturday, according to FanDuel Sportsbook. They’ve been favored in every game this season. The Chiefs have embraced the underdog role in the playoffs, going on the road to beat Buffalo and Baltimore.

Reid and Mahomes are chasing Bill Belichick and Brady. They’ve got to win four more Super Bowls to match them.