SEATTLE -- The Mariners’ chances for a comeback seemed so improbable for the first three hours of Opening Day that it was almost fitting that the way in which they came back to stun the Giants in the 10th inning -- on a walk-off walk to Jake Fraley -- was just as improbable.

Seattle came back from down five runs entering the eighth inning and somehow, some way, left T-Mobile Park on Thursday with an 8-7 victory to start the 2021 season, one that they have huge ambition for.

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Evan White scored the game-winner as the automatic runner that began the 10th on second base as part of the extra-innings rules package introduced last season, making the Mariners the first team since the 1997 Expos to draw a free pass for a Game 1 victory.

Seattle also became the sixth team in the Modern Era (since 1900) to come back from down five runs as late as the eighth inning on Opening Day and win, according to Elias. And it was the fourth time in franchise history that the Mariners walked off on Opening Day.

While Fraley’s walk brought dramatic finality, there were four other significant plays that went into the Mariners’ come-from-behind victory. Here is a breakdown of each:

Trammell’s eight-pitch walk

Taylor Trammell exorcised the incredibly high emotions he evoked while making his Major League debut with a plate appearance that defined the victory in the eyes of manager Scott Servais. With no outs in the eighth inning, Trammell worked an eight-pitch walk from Jarlin García to register his first career RBI and spark the momentum in a six-run inning after the Mariners were mostly lifeless on offense to that point.

The 23-year-old Trammell -- who played his way onto the team with a stellar Spring Training -- showed poise under pressure, pitch recognition by fouling off two balls with two strikes and patience by watching balls three and four go by without pressing.

“Absolutely, because that AB, he made really good pitches. ... He tunneled his pitches really well,” Trammell said. “His fastball came out pretty well with his four-seam and then his slider as well. Like I said earlier, compete. I just competed that AB.”

MLB Pipeline’s No. 100 overall prospect, Trammell contended that it wasn’t his sequence that made the difference, but rather that of Dylan Moore, who followed with an RBI double. Moore then came around to score the go-ahead run on an error when Giants first baseman Brandon Belt hurled an attempted double-play ball hit by José Marmolejos into left field.

Though that epic eighth wound up not being the end-all -- new closer Rafael Montero surrendered a game-tying homer to Alex Dickerson in an 0-2 count in the ninth -- Trammell continues to impress after coming over in a Trade Deadline deal with the Padres last Aug. 31.

Haniger’s sliding catch

Mitch Haniger positioned Fraley for the walk-off by making a remarkable, inning-ending catch down the right-field line that robbed Buster Posey of a go-ahead RBI double in the top of the 10th. Haniger covered 109 feet in 5.6 seconds and converted a sliding play that had just a 55% catch probability, according to Statcast.

“I was going absolutely crazy,” Trammell said of his view of the play from center field. “It was sick. I'm a strong believer that this game is a game of momentum, a game of vibes as well. So the momentum and the vibes were in our favor. ... There was no doubt in my mind that we were going to win this game.”

Haniger, who went 1-for-5 with one run scored, was playing in his first game since June 6, 2019, after multiple surgeries and setbacks that derailed his recovery. Known more for his bat, especially after looking stellar -- and healthy -- with three homers in Spring Training, Haniger showed how valuable his glove will be in right field.

“That was pretty big,” Servais said. “Mitch Haniger, it seemed like he was all over the place tonight. ... He hadn't played a game like that in quite some time.”

Getting Gausman out

The Mariners mustered just two hits through the first seven innings and failed to generate any offensive traction, thanks to a stellar start by Giants right-hander Kevin Gausman, who kept Seattle’s first 11 hitters off the bases.

But the Mariners were finally able to break through in the seventh when White led off with a double and Moore scored him with a sacrifice fly. That swung open San Francisco’s bullpen door -- and the Mariners’ momentum, especially after No. 1 starter Marco Gonzales admittedly didn’t have his best stuff, giving up a career-high-tying three homers and three walks.

“When we got [Gausman] out of there, we really focused on just having good ABs, and it was contagious hitting,” Moore said. “The energy was high in the dugout for sure.”

The return of fans

The pomp and circumstance of Opening Day was palpable on Thursday at T-Mobile Park, where fans were welcomed back for the first time in 550 days, a span of more than a year and a half. A sellout crowd of 8,174 showed how eager they were to be immersed in the pageantry at long last, and their roars at times made it sound like there were at least thrice that number in attendance -- if not more.

“It didn't feel like 9,000 -- it felt like a lot more,” Gonzales said. “You could feel the intensity. You could feel the anticipation that people had getting out here, and we felt a lot of love from our fans.”

“You guys made a huge difference in that ballgame,” Servais said of the fans. “It's not like turning up the crowd noise -- it's real. And our players felt it. The other team felt it. So I think all of whatever it was the 9,000 or 10,000 people that were in the stadium, thank you. It's great to have you back.”