Sean Payton's regret began settling in during the Denver Broncos' flight home from Indianapolis on Sunday.

The Broncos had just suffered a 29-28 loss that was decided on the game's final play, a 45-yard field goal by Colts kicker Spencer Shrader. The winning boot represented a mulligan after Denver was deemed to have committed a personal-foul leverage penalty on Shrader's missed 60-yard attempt. The infraction on linebacker Dondrea Tillman was ruled correctly because Tillman put his hand on an opponent and pushed in an attempt to gain height on his leap, Payton said Monday, so his ire did not rest with the officials. It stemmed from the fact that he called for an aggressive field-goal block play on a low-probability kick. Shrader had never attempted a kick of longer than 48 yards in his two-year NFL career, and no kicker has ever made a field goal of 60 yards or more during a regular-season game at Lucas Oil Stadium.

"We had a certain field-goal block in the event of a game-ending field goal," Payton said. " ... But that's on me in that situation. It's not on Darren (Rizzi, the Broncos' special teams coordinator). It's not on Tillman. ... My big regret flying home: that's more for a closer field goal. That's more for a gimmie than a 60-yard attempt, and that's on me."

Payton also said "the alignment got mixed up" on Denver's field-goal block unit on the initial kick. The Broncos wanted D.J. Jones and Tillman, whom Payton noted is a strong leaper, to focus their rush against defensive tackle Grover Stewart, who is the left guard on the Colts' protection unit. The idea was to have Jones push down on Stewart and give Tillman a clean leaping lane without having to push off anyone.

"That's legal," Payton said.

However, just before the ball was snapped, Tillman switched spots with Eyioma Uwazurike, creating a different configuration for Denver's front.

"Right at the last minute, they flipped sides inside, so now we're on a different offensive blocker," Payton said. " ... We ended up on the wrong side and we didn't execute it. Before any and all of that, though, we should be working a normal interior rush with a 60-yard attempt."

Tillman said after Sunday's game his job was "just to make a play, really," but the misalignment compounded the ill-fated decision to attempt an aggressive field-goal block.

Leverage penalties are relatively rare, with only 18 of them called league-wide since the start of the 2020 season, according to TruMedia. Only six of those calls have been made in the fourth quarter during that span, but Denver's penalty Sunday was the first to grant a kicker a second game-winning opportunity following a miss.

Sunday marked the second time in as many seasons the Broncos lost a game on a final-play field goal gone wrong. In Week 10 at Kansas City last season, Chiefs linebacker Leo Chenal blocked Wil Lutz's 35-yard field-goal attempt as time expired, bulldozing over Alex Forsyth on the inside of Denver's protection unit. Assistant head coach Mike Westhoff, who helped oversee Denver's special teams unit, resigned the following week, citing health problems. The Broncos then fired special teams coordinator Ben Kotwica after the season.

Two games into a new season, with Rizzi now serving as Denver's special teams coordinator, the Broncos were once again left to grapple with an excruciating loss that came under improbable last-play circumstances. The Broncos responded after the loss to the Chiefs by winning their next four games en route to the team's first playoff appearance since 2015.

Payton said he expects similar resolve from the Broncos as they begin a difficult stretch of their schedule with a Week 3 road game against the Los Angeles Chargers, but the focus in the hours after Sunday's loss was on correcting self-inflicted miscues that went well beyond the final-play disaster. Payton noted the Broncos are near the bottom of the league with five turnovers through two games. He lamented a lack of efficiency in Denver's red-zone operation offensively and cited too many "busted fire-zone coverages" on defense that left Colts running back Jonathan Taylor with gobs of open real estate after making catches out of the backfield. He called it "concerning" that Denver has given up points on opening drives two weeks in a row.

"We have to start with ourselves as teachers, as coaches, and look very closely at, 'How can we improve in these areas?'" Payton said. "And then B, 'How can we apply it and make sure there's that urgency here in Week 3, Week 4, to clean things up?' It's hard to sustain success in our league as a yo-yo team, up and down. So that's the race we're in right now."

Broncos' Sean Payton regrets play call that led to game-deciding penalty: 'That's on me'