TAMPA, Fla. — Rams kicker Matt Gay’s kick sneaked inside the left upright as the game’s final four seconds ticked away, giving Los Angeles a 30-27 win over Tampa Bay on Sunday to reach the N.F.C. championship game.

The Rams’ lead, which had ballooned to as many as 24 points, had evaporated late in the game, and Buccaneers running back Leonard Fournette scored the game-tying touchdown on the drive preceding the game-winning kick.

RAMS WIN. WHAT A GAME.#LARvsTB | #NFLPlayoffs pic.twitter.com/FyEPdaXaqd

— NFL (@NFL) January 23, 2022

But Rams quarterback Matthew Stafford connected with Cooper Kupp on a 44-yard pass, then hustled his team downfield to spike the ball to set up Gay’s field goal.

The Rams, on paper, appeared to be the better team going into the game. They had an offense loaded with receiving weapons and an experienced quarterback, in Stafford, at the helm of the offense.

They had a defense with one of football’s best players, in Aaron Donald. And they had dealt with far fewer injuries than Tampa Bay.

But the Buccaneers had the ultimate advantage: the 44-year-old quarterback Tom Brady, who had played in more playoff games than most of the players left in the postseason and who is just a few years removed from helping his former team, the New England Patriots, overcome a 28-3 third-quarter deficit against Atlanta to win the Super Bowl.

Tampa Bay’s attempt at a comeback followed a game marred by an overall stagnant offense and defensive miscues. And though it looked like Brady could lead another dramatic postseason comeback, the Rams, led by Stafford and their defense, held on with the walk-off field goal. They will face the San Francisco 49ers, who beat the Green Bay Packers on Saturday, in the N.F.C. championship game.

The Rams never trailed, but Los Angeles gave the Buccaneers plenty of opportunities to chip away at its lead.

With less than five minutes remaining, Brady heaved a pass up to receiver Mike Evans, who had a one-on-one matchup against the star defensive back Jalen Ramsey, and Evans hauled in the pass for a 55-yard score. That made it a 7-point game.

In the third quarter, Tampa Bay recovered its second fumble of the game — it recovered four fumbles total — and turned the takeaway into 7 points. Fournette, who played in his first game since Week 15 after returning from injured reserve, punched the ball in from the 1-yard line.

That cut the Rams’ lead to 14 and energized Raymond James Stadium’s home fans, who’d grown quiet as their team struggled through the better part of three quarters.

Clinging to its two-possession lead, Los Angeles forced two Tampa Bay turnovers on downs late in the game to clinch its spot in the conference championship game.

It was far from a perfect game by either team. They combined for six turnovers.

The Rams faced little resistance from the Tampa Bay defense early and scored on three of their first four possessions.

Stafford, who’d had a topsy-turvy regular season characterized by 41 touchdowns and 17 interceptions, looked comfortable early.

He had nearly 200 passing yards before the end of the first quarter. He finished with 366 yards and two touchdowns, compared with 329 yards for Brady, who threw a touchdown and an interception.

On the Rams’ first touchdown drive, the Buccaneers had gifted them 15-yards thanks to a taunting penalty on Ndamukong Suh. Stafford hit an unlikely target, Kendall Blanton — he hadn’t had a touchdown all season — to give the Rams a 10-3 lead.

Los Angeles scored on their next possession after a blown coverage by the Buccaneers’ secondary, which struggled in coverage against the Rams when the teams met in Week 3.

The misstep allowed Kupp, who led the league in all of the major receiving categories in the regular season, to log a 70-yard score.

The Buccaneers were without their All-Pro right tackle Tristan Wirfs, who had an ankle injury, and it showed, Tampa Bay struggled in pass protection for much of the game.

Brady was sacked three times.