Analytics Recap: Kansas City Chiefs Lose to Tampa Bay Buccaneers 31-9 in Super Bowl LV

What do the advanced metrics have to say about the Kansas City Chiefs' 31-9 loss to the Tampa Bay Buccaneers in Super Bowl LV?

The Kansas City Chiefs fell just short of making history and becoming back-to-back Super Bowl champions as their season came to a close with a 31-9 loss in Super Bowl LV on Sunday night. The Chiefs finished the season with 16 wins and three losses for the second consecutive season and will now head into the offseason with talk of the Super Bowl runner-up curse, as three of the last five Super Bowl runners-up have missed the playoffs and only one team in the last 48 years has gone from losing the Super Bowl to winning it the following season.

Here are the advanced numbers from the Chiefs' loss to the Buccaneers from Ben Baldwin's rbsdm.com.

EPA = Expected Points Added, SR = Success Rate, 1st% = First Down Rate

It was a brutal showing for the passing offense and passing defense of the Chiefs, as the Bucs' EPA per pass play was 0.36 and the Chiefs' EPA per pass play was at a dismal -0.19. Interestingly enough, it was the early downs that really made it for the Bucs, as they had a 0.40 EPA per play on early downs (0.18 rush, 0.61 pass), compared to a -0.77 EPA per play on late downs (-1.23 rush, -0.48 pass). For the Chiefs, their late-down passing failures (with a total EPA of nearly -9) were wildly uncharacteristic for such a usually dominant offense.

Clyde Edwards-Helaire and Travis Kelce seem to be the only two Chiefs weapons that really stepped up in this one. Edwards-Helaire finished with a 3.4 Total EPA and 67% success rate over 12 plays, while Kelce finished with 3.2 Total EPA and a 65% success rate over 17 targets. The Buccaneers' weapons performed at a higher collective level, with Rob Gronkowski earning 7.2 EPA, Mike Evans racking up 6.4 EPA and Leonard Fournette having 6.1 EPA. Big games for the Bucs weapons, not so much for the Chiefs. 

aDoT = Average Depth of Target, CMP% = Completion Percentage, xCMP% = Expected Completion Percentage, CPOE = Completion Percentage Over Expectation (Completion Percentage minus Expected Completion Percentage), xQBR = Expected Result for ESPN's Quarterback Rating metric

Super Bowl LV brought the worst EPA numbers of Patrick Mahomes' career. It is a real shame that Mahomes' numbers look as bad as they did on the biggest stage, but the saddest part is that the quarterbacks here really played about even, as Pro Football Focus (PFF) gave Tom Brady a 66.9 grade and Mahomes a 65.8 grade. Mahomes was completely let down by his supporting cast in this one, having 30 pressures allowed and three dropped passes by his teammates, while Brady was greatly supported by his supporting cast, with four pressures allowed and zero dropped passes.

Interestingly enough, the Chiefs had three of the five biggest plays of the game for EPA in their favor, with the goal line stuff on 4th-and- 1 coming in second place, the botched snap on 3rd-and-10 that Brady fell on in fourth and a Mahomes pass to Demarcus Robinson on 4th-and-3 in fifth. Unfortunately, sixth, seventh and eighth all went in the Buccaneers' favor and all three were touchdowns. Plus, the Buccaneers' two biggest plays were an interception and a turnover on downs.

The Chiefs began the game with a 59.9% win probability, but it mostly went downhill from there. By the end of the first quarter, it fell to 52.2% and then the Bucs held it for nearly the rest of the game, with a short jump back in the Chiefs' favor in the early-to-mid-second quarter. With the Bucs' late first-half touchdown, thanks in part to some questionable Chiefs timeouts, the Bucs' win probability jumped from around 61% to around 87%. The Bucs hit a 95% win probability in the mid-third quarter and a 100% win probability in the early fourth quarter. 

The Chiefs finished the season as the second-best team for EPA, trailing only the Green Bay Packers with their first-ranked Offensive EPA per play and ninth-ranked Defensive EPA per play. The Chiefs, meanwhile, finished with a second-ranked Offensive EPA per play and 20th-ranked Defensive EPA per play. Rounding out the top five teams for the season were the Buffalo Bills with a third-ranked Offensive EPA per play and 14th-ranked Defensive EPA per play, Tampa Bay Buccaneers with a fifth-ranked Offensive EPA per play and eighth-ranked Defensive EPA per play and Cleveland Browns with a sixth-ranked Offensive EPA per play and 16th-ranked Defensive EPA per play.

The Chiefs finished the season with the league's top early-down passing rate with a 63.1% rate, just leading the Buffalo Bills with their 63.0% rate, Houston Texans with their 62.4% rate, Pittsburgh Steelers with their 61.4% rate and Seattle Seahawks with their 60.0% rate. This is the second consecutive season where the Chiefs led the NFL in early-down passing rate, as they had a 66.1% rate in their 2019 Super Bowl-winning season when only the Miami Dolphins (61.9%) had a rate of 58% or higher. In 2018, the Chiefs finished second behind the Steelers with a 64.6% rate compared to the Steelers' 65.0% rate. 

For the entire NFL season, Patrick Mahomes finished with the second-highest EPA per play (0.339), tied for eighth-highest CPOE (2.9) and tied for second-highest EPA+CPOE (0.184). The other top quarterbacks this season were Aaron Rodgers (0.225 EPA+CPOE and 0.415 EPA per play), Josh Allen (0.184 EPA+CPOE and 5.8 CPOE), Tom Brady (0.170 EPA+CPOE and 0.308 EPA per play), Ryan Tannehill (0.170 EPA+CPOE and 0.304 EPA per play), Deshaun Watson (0.165 EPA+CPOE and 6.5 CPOE), Baker Mayfield (0.164 EPA+CPOE) and Justin Herbert (0.154 EPA+CPOE). The name here that should interest Chief fans the most is obviously Herbert, as he is a rookie in the AFC West who played incredibly well, finishing seventh in EPA per play and tied for eighth with Mahomes in CPOE. 

For the entire 2020-21 NFL postseason, Patrick Mahomes finished as the second or third best QB in these metrics. Mahomes' postseason EPA+CPOE composite score fell from a clear-best 0.263 to a second-best 0.172, trailing only Baker Mayfield's 0.200. For postseason EPA per play alone, Mahomes went from a 0.495 EPA per play in the first two games, which ranked clearly in first, to 0.299 after the Super Bowl, finishing in third behind Mayfield's 0.327 and Tom Brady's 0.326. Mahomes also fell from an 8.9 CPOE to a 3.0 CPOE for the postseason after the Super Bowl, which took him from first to fourth.

For more Kansas City Chiefs analytics and analysis, follow @SIChiefs and @WichitaChiefSam on Twitter.

Read More: Patrick Mahomes to Have Surgery to Repair Turf Toe on Wednesday — What's Next?