SEATTLE -- From the deepest depths of despair to the most exhilarating euphoria, the Mariners rode an unhinged roller coaster of emotions over an electrifying ninth inning on Sunday, which culminated with an 8-7 walk-off win over the Braves.

It had anguish. It had gloom. But, according to their 21-year-old star rookie, it never had doubt.

Julio Rodríguez crushed a game-tying homer off Kenley Jansen, then Eugenio Suárez followed with a walk-off blast to catapult the Mariners to their most thrilling victory yet, immediately after Seattle’s lights-out bullpen put them in peril by surrendering five runs with two outs in the top of the ninth.

The Mariners went from cruising to a dominant win over first-place Atlanta all afternoon, to being soberly reminded why the Braves are the defending World Series champions, to back on top in one of the most topsy-turvy ninth innings seen in MLB this season. Throw in the sold-out crowd of 45,245, and that these two teams are on a fast track to the postseason, and Sunday’s matinee had all the ingredients of an October instant classic.

“That’s a playoff game right there,” said Marco Gonzales, who spun six brilliant innings. “That’s how we need to treat that.”

To reach the highest of highs, the Mariners had to descend to the lowest of lows.

Atlanta was down to its final strike in a full count with two outs despite reliever Diego Castillo walking his first two batters, but Michael Harris II sent just about all of Seattle into code red with a 433-foot moonshot that might warrant him early consideration for the Home Run Derby here next summer.

Mariners manager Scott Servais then turned to Paul Sewald, perhaps later than most anticipated, but Sewald -- despite numerous crises averted -- gave up a line-drive single to Eddie Rosario and the would-be dagger, a two-run blast by Robbie Grossman into the right-field bleachers that pushed the Braves ahead. It was the first time since a June 21, 2011, loss to the Nationals in which the Mariners’ bullpen had a four-run lead with two outs in the ninth inning and then gave up five or more runs.

Sewald, who’s been one of the AL’s best leverage relievers the past two years, was deflated -- but the position players quickly quelled him in the dugout.

"Every single guy said the same thing: 'You've saved us 25 times this year. Every once in a while, it's OK for us to save you,’” Sewald said. “So I'm very appreciative of the fact that they hit those two homers in the ninth."

Even for a club that thrives in late-innings thrillers, if self doubt crept in, it went unseen -- especially for Rodríguez, who despite the despair flashed his megawatt smile while running in from center field ahead of his fateful at-bat.

What gave him such conviction that the Mariners would so dramatically pull through?

“Because I believe in this team,” Rodríguez said. “I feel like everybody comes in every day to put the work in. I feel like everybody is always doing the best for the team. I feel like we compete and we just show up. I feel like we have the chance, we have the guys to compete against anybody, and that’s why I was confident that we’d be able to come through in that last inning, because I know what we’ve got on this team.”

In a 1-1 count against Jansen, a three-time All-Star with 57 games of playoff experience, Rodríguez saw a hanging slider and didn’t miss, connecting for a whopping 117.2 mph shot off the left-field scoreboard -- the highest exit velocity on a Mariners homer since Statcast began tracking in 2015.

“Every time he’s on base, we have a chance to score,” Suárez said. “I swear, I told everybody: ‘If Julio gets on base, we’ve got a chance to win this game.’ It just happened. Like I always say, everything Julio is doing is special.”

Rodríguez might be the Mariners’ best player, but Suárez has been their hottest of late. Both homered twice on Sunday, and Suárez has hit four in his past four games and 11 in his past 22, none bigger than the walk-off, just the second of his career, both this season.

Also in a 1-1 count, Suárez pummeled a low-and-in fastball into the home bullpen and sent T-Mobile Park into a seismic shake, putting a bow on arguably the biggest win of the season -- so far.

“I know what I can do,” said Suárez, who lived up to his mantra of ‘Good Vibes Only.’ “I trust myself and I just come here to enjoy the game. It doesn’t matter the situation. I’ve been around a little bit, and I’ve learned that from guys like Miguel Cabrera and Joey Votto. Keep calm, and that’s what I try to do every day.”

The victory pushed the Mariners’ playoff odds up to 99.8%, per FanGraphs, and they pulled into a tie with Tampa Bay for the top AL Wild Card spot, just a half-game ahead of Toronto for the third and final spot. Six games, plus a tiebreaker, separate Seattle from Baltimore, the first team on the outside looking in.

There are 22 games remaining and the drought is nearing an end, barring an epic collapse. But just how likely is a spiral at this point, especially after a gut-check victory over the defending champs that screamed, “We belong.”

These Mariners are showing that they’re a playoff-caliber team, and Sunday was the best example why.