LOS ANGELES — The 2018 Boston Red Sox opened their spring training camp on Valentine’s Day, notched the season’s first win on Good Friday, and by Mother’s Day were playing at a .700 clip. By Independence Day, when they shut out the Washington Nationals, they were in first place to stay, and by Labor Day they were 51 games above .500. On the final day of the regular season, they notched their 108th win, and on Columbus Day they crushed the New York Yankees by 15 runs in the playoffs’ opening round.

And on Sunday night at Dodger Stadium, 2,600 miles from home and three days shy of Halloween, the Red Sox put the finishing touches on one of the great seasons in recent baseball history. A 5-1 victory over the Los Angeles Dodgers in Game 5 of the World Series completed a methodical, 11-3 march through this postseason — annihilating three excellent teams along the way, the Yankees, Houston Astros and now the Dodgers — and pushed their win total, regular and postseason combined, to 119.

Once mocked as a hapless, snakebit and even cursed franchise, which once went 86 years without a title, the Red Sox have now won the World Series four times in a 15-season span. And this one completed an unprecedented, geographical grand slam of clinches, with the Red Sox celebrating a World Series title on diamonds in all four time zones in the continental United States — 2004 in St. Louis, 2007 in Denver, 2013 in Boston and now 2018 in Los Angeles.

“This is a special team. We had to beat, what, two 100-win teams to get here?” slugger J.D. Martinez said, noting the Yankees’ and Astros’ win totals. “That doesn’t happen too often.”

David Price, once mocked as a hapless, snakebit and even cursed pitcher in the postseason, who once made 11 straight October starts without winning one, delivered seven remarkable, one-run innings Sunday night, despite a grueling recent workload that included a start just four days earlier and a relief appearance in Game 3, just two days prior.

“I hold all the cards now. And that feels so good. That feels so good,” Price said directly to the assembled media in his postgame news conference. “I can’t tell you how good it feels to hold that trump card. You guys have held it for a long time. You’ve played that card extremely well, but you don’t have it anymore. None of you do, and that feels really good.”

The Red Sox offense, meantime, which led the majors in runs this season but had disappeared for stretches in this series, ambushed Los Angeles ace Clayton Kershaw for three home runs, in what could have been the great left-hander’s final appearance for the Dodgers.

When Price came out of the game following a leadoff walk in the eighth, a shocking number of Red Sox fans among the sellout crowd of 54,367 stood and roared for the veteran lefty, who stared hard into his dugout, at his teammates, and tapped his chest before descending the dugout stairs.

“There’s a lot of people who gave up on him throughout the season,” Red Sox Manager Alex Cora said of Price. “A lot of people who gave up on him after his outing against New York [in the Division Series]. But we knew he’s one of the best pitchers in the big leagues. And he cares.”

The final six outs came with breathtaking force: workhorse reliever Joe Kelly entered in relief of Price and struck out a trio of high-powered Dodgers pinch hitters to close out the eighth, and lefty Chris Sale, scratched in favor of Price as the Game 5 starter, closed it out by striking out the side in the ninth.

At the final out — Manny Machado, going down swinging and sinking to one knee — Sale flung his glove, threw both hands in the air and awaited the crush of teammates that was headed his way from the dugout, at a full sprint, to engulf him.

In their raucous postgame clubhouse, the Red Sox sprayed champagne, draped arms across each other’s shoulders and sang along to a greatest-hits soundtrack inspired by their conquests this month: “New York, New York,” “California Love,” “Hotel California.”

“I can’t hold back my tears,” said pitcher Rick Porcello, who, like most of the Red Sox’s playoff rotation, toggled between starting and relieving. “I’ve never felt anything like it. I apologize. I know I’m supposed to be all rah-rah and hold my fists in the air. [But] it’s more than just about money and showing up for your job every day. You gotta put your heart into it.”

The Dodgers, meanwhile, watched a visitor celebrate a World Series clincher on their home turf for the second straight year, after the Astros did it in 2017. It marked the 12th time since their 1988 World Series title that the Dodgers had made the playoffs but fallen short of a championship, including each of the past six years.

“I think you have to realize we are a really good team to get to the World Series two years in a row,” Kershaw said. “It may not be a personnel thing [that made the difference]. It might just be a play-better thing.”

On a Red Sox roster full of MVP candidates, former Cy Young winners and nine-figure contracts — collectively forming the highest payroll in baseball — the player named the World Series MVP was Steve Pearce, a journeyman now with his eighth big league organization whom Boston acquired in June from Toronto for a low-level prospect. Pearce hit two homers Sunday night, one each off Kershaw and reliever Pedro Baez, Pearce’s second and third homers of the series, to go along with a .333 batting average, one double and eight RBI.

“Baseball is a funny game,” Pearce said. “You never know where the game will take you. . . This has been a lifelong journey. And to be here now is a dream come true.”

Kershaw has until three days after the end of the season to decide whether to exercise an opt-out clause in his contract — and has given no public indication what he intends to do — so when he took the mound Sunday night, the crowd had to treat it as if it were possibly the last time they would see him in a Dodgers uniform.

As has been the case for most of this season, his 11th in the big leagues, this was the diminished version of Kershaw, his fastball barely cracking 91 mph, his slider lacking its vintage bite. Six pitches into the game, the Red Sox had a 2-0 lead, with Pearce jumping on a first-pitch fastball, 92 mph and thigh-high, for a two-run homer. The batter before, Andrew Benintendi, had singled up the middle.

Price and Kershaw hold the distinction of owning the largest contracts of any pitchers in history — nearly half a billion dollars’ worth between them — and they also share checkered histories in the postseason. Both gave up homers in the first inning, with Dodgers leadoff man David Freese connecting off Price. It was 2-1 at the end of the first, and that’s where the score remained for the next four innings.

At the last purple sunset of 2018 beyond Dodger Stadium, the countdown on the Dodgers’ season — and quite possibly Kershaw’s tenure with the team — had begun, both of them measured in outs. When the sixth inning began, and the Dodgers still trailed by a run, the number was down to 12.

Then Mookie Betts homered off Kershaw in the sixth, on a low slider over the middle of the plate. For Betts, it was his first career postseason homer in his 86th career postseason at-bat, and it snapped an 0-for-13 stretch that was his longest 0-fer of the season. An inning later, Martinez launched a blast to center on a 90-mph fastball, marking the first time all season Kershaw had given up three homers in a game.

The Red Sox did many things well in this postseason, losing just a single game in all three rounds, but one thing they did especially well was destroy lefties. They went 7-0 in games started by southpaws, including victories over Cy Young winners Kershaw, Dallas Keuchel and CC Sabathia.

Giving the ball to Price on Sunday night, four days after he started and won Game 2, two days after he pitched in relief in Game 3 and one day after he warmed up during Game 4, spoke to both a growing confidence in Price and a lingering concern over Sale’s shoulder. Game 5 had been penciled in as Sale’s, but the Red Sox wanted to give him extra rest and save him for a potential Game 6.

Price took such deep breaths between pitches, his chest threatened to blow out the buttons of his blue uniform top. His pace between pitches pivoted between deliberate and interminable. He gave the Dodgers few chances. With one out in the third, Martinez, the Red Sox right fielder, lost Freese’s flyball in the lights, with Freese credited with a triple. But they couldn’t get the run home.

It was like that, more or less, this entire series for the Dodgers, who won only one game — the zany, wild, 18-inning marathon in Game 3. They never seemed overmatched exactly, despite being outscored 28-16 across five games, but they simply could never get the big hit, secure the big out or make the right move with the same frequency as the Red Sox, who hit .353 with runners in scoring position and scored 17 of their 28 runs with two outs.

There was one very good team playing in these five games, and there was one great one. The former heads into another winter wondering what it will take to win it all. The latter will be parading down Boylston Street sometime around Halloween, and the glow from Sunday night’s cathartic ending might last straight through to Christmas.