SEATTLE -- It was shaping up to be another tough day at T-Mobile Park, featuring a stellar start from the rotation and nothing but three bad-luck moments at the plate that led to no run support. 

But the Mariners crept their way back with their fourth walk-off win of the year, a 2-1 victory over Oakland that could’ve easily gone the other way in a tense matinee. Facing a five-man infield, Abraham Toro sailed a 108 mph line drive into the right-center gap that handily scored Marcus Wilson from third base to set off a celebration on the infield.

It was a much-needed victory in the context of the schedule, against a last-place club and the 17th contest in an 18-game stretch against teams under .500, a window in which Seattle is now 10-7. After Sunday’s series finale, the Mariners will head to San Diego for a two-gamer before returning home for four against Toronto.

Here are three key moments that led to the victory:

Kirby shows ace-level stuff
The most prominent development was the superb showing from George Kirby, who completed seven innings, tying his career high from the Minors. He also racked up nine strikeouts, tying his season high, while throwing 100 pitches, more than any in a single start since he was selected in the first round of the 2019 Draft.

His lone blemish came via a rare, uncharacteristic walk -- leading off the game, to boot -- which came around to score and put the Mariners down immediately. Kirby, visibly frustrated with himself, went on to retire 19 of his final 21, including 13 straight at one point.

“I'm just trying to stay even-keeled all the time,” Kirby said. “I don't want to get too high or too low. I’ve just got to do a little better job, come out of the chute really aggressive. I think I've been lacking that a couple starts in a row.”

His biggest moment was completing the seventh against two lefties with southpaw Ryan Borucki warming. For a rookie in just his 11th career start, it was the type of sequence that he can build upon.

“I was super pumped to go back here for the seventh. It was really awesome,” Kirby said. “Big time. I needed this one. It's a good confidence booster.”

Kirby, who has now faced Oakland three times, has the second-highest strikeout-to-walk ratio (7.25) through a pitcher’s first 11 career Major League starts in AL/NL history (excluding openers), trailing only the Yankees’ Masahiro Tanaka, who posted a 7.33 mark in 2014.

“He had a really good fastball today,” said Oakland’s veteran catcher, Stephen Vogt. “It plays up from the miles per hour that you see. He’s got really good extension, and he lives at the top of the zone. He threw just enough curveballs to keep us honest, and his changeup is a pretty good pitch, too, when it’s located. He’s got three plus pitches and throws the slider to righties as well.”

Overcoming the five-man infield
With no outs against A’s reliever Lou Trivino, acting manager Brad Ausmus opted to bring Ramón Laureano in from right field to play third base, and have the rest of the infield play on the grass. Toro, whose struggles this season have been well-chronicled, turned to the dugout and Eugenio Suárez, who gestured a deep breath signaling not to overthink the moment.

“He just told me to calm down because it’s easy to get amped up in those situations,” Toro said. “I listened to him, took a deep breath and it worked out."

Toro was only in that situation thanks to the plate appearance prior, when Cal Raleigh reached to load the bases on a chopper that was bobbled by Nick Allen around the middle of the five-man infield.

It was an odd and wild way to walk it off, but the Mariners will certainly take it.

Upton’s big homer
Seattle had been playing from behind nearly all afternoon and was down to its final four outs before Justin Upton broke through with a huge, game-tying homer in the eighth -- the 325th of his career, but the first as a pinch-hitter.

“I'm definitely not used to it, but I got a pinch-hit at-bat the other night,” Upton said. “You try to just find ways to figure it out. You've just got to try to change your mindset a little bit going into the box, and I was able to execute.”

Upton is hitting just .152/.282/.273 (.555 OPS) in 12 games since joining the Mariners on June 17, but manager Scott Servais has pointed out that the 16-year veteran and four-time All-Star has brought in an intangible attribute that they were lacking: a veteran presence, something they haven’t really had among position players since Mitch Haniger and Tom Murphy went down with significant injuries.

“He has done such a fantastic job in our clubhouse,” Servais said. “And I know the normal fan doesn't see that, but having that veteran around has really helped a lot of our guys. He speaks up in meetings. He's really adding a lot, and great to see him contribute.”