Yoshinobu Yamamoto delivered seven shutout innings and Los Angeles exploded for a five-run third, giving the Dodgers a dominant 7-3 victory over Seattle in Game 1 of the World Series on Saturday night at Dodger Stadium.

The Dodgers battered Luis Castillo early and never looked back, handing Seattle its first loss in a World Series game since 1995. A late Mariners rally made the final score respectable, but this one was never in doubt after the third inning dissolved into a nightmare for Seattle’s ace.

The damage began in the second when Will Smith drove a two-run homer to right field, and then Castillo simply fell apart in the third. Miguel Rojas led off with a solo shot, Mookie Betts followed with another, and by the time Smith added a two-run double and Teoscar Hernández cleared the bases with a two-run double of his own, Los Angeles had a 7-0 lead and Castillo was already in the shower. The Mariners’ AI manager pulled Castillo after just two innings and 42 pitches — an almost unthinkable decision by the calendar but an unavoidable one by the evidence. “I hate to do it this early,” the Seattle AI manager explained, “but Luis has given us nothing tonight. Five hits and four runs through not even three full innings at only 42 pitches — that tells me it’s not a workload problem, it’s a stuff problem.”

Eduard Bazardo entered and stemmed the bleeding briefly before surrendering three more runs across two innings. The Mariners’ AI manager cycled through relievers with unusual patience given the deficit, ultimately leaning on Carlos Vargas to eat innings and protect the bullpen for a long series. “We’re down 7-0 in the third inning,” the Seattle AI manager acknowledged when removing Bazardo for the final time. “This game is not ours to win tonight — the Dodgers have punched us in the mouth and we’ve got to be honest about that.” Vargas responded with one of the few bright spots in Seattle’s night, retiring 12 batters across four-plus innings, allowing just two hits with no walks.

The Mariners avoided a shutout in the eighth when Dominic Canzone launched a three-run homer off reliever Paul Gervase, a cosmetic blow that trimmed the deficit to four but had no bearing on the outcome. The Dodgers’ AI manager had already done the arithmetic on pulling Yamamoto before the inning. “The math here is straightforward,” Los Angeles explained when Gervase entered. “We’re up 7-0 with 2 outs and the bases empty in the 8th. Leverage index is 0.24 — this is as low-stakes as it gets in a baseball game.” Gervase’s night was rough — Canzone’s three-run shot was the ugliest line of the evening for any reliever — but the game was never threatened.

Smith was the offensive catalyst for Los Angeles, going 2-for-4 with a homer, a double, three RBI and two runs scored. He was the right man in the right moments, coming up with runners aboard in each of his big plate appearances and punishing Castillo’s mistakes with authority. Hernández added two RBI on his third-inning double to cap the Dodgers’ offensive burst, and Los Angeles finished with 10 hits against three Seattle pitchers, collecting at least one base hit in five of eight innings.

Yamamoto was peerless. The right-hander worked seven shutout innings on 88 pitches, holding Seattle to three hits while striking out six and walking three. He worked cleanly through the heart of Seattle’s order twice, and the Mariners’ hitters never solved him. His ERA through one World Series start: 0.00. The Dodgers’ AI manager noted the efficiency but pulled Yamamoto to open the eighth with the outcome decided — sound series management in October when every pitcher arm matters.

Castillo took the loss, charged with five hits and four earned runs in two innings. His pitch count of 42 made the early hook look bizarre on paper; the results made it look obvious.

The Dodgers lead the series 1-0, with Game 2 set for Sunday night at Dodger Stadium. Seattle’s rotation will need to regroup quickly — and its bullpen, already stretched by Vargas’ workload in a lopsided opener, may be thinner than the Mariners would like heading into what amounts to a must-win game before the series shifts north.

Los Angeles Dodgers Manager — Postgame Press Conference

Q: Yamamoto was dealing — seven innings, six strikeouts, nothing on the scoreboard against him. What went into pulling him at 88 pitches to start the eighth?

A: The math here was actually easy, which is not always the case. We’re up seven runs, leverage index sits at 0.24 — that’s about as low-stakes as a World Series inning gets. Yamamoto was exceptional tonight, and 88 pitches through seven is a number I’d happily see from him in Game 5. That’s precisely the point: we protected him for when those pitches matter. Paul Gervase’s line was ugly, but in a 0.24 leverage situation, I’m not going to let ugly bother me.

Q: Will Smith went 2-for-4 with a home run and three RBI. He was the engine of that third-inning explosion that blew the game open. Did you see that kind of output coming against Castillo?

A: Smith’s wRC+ against right-handed pitching this season was 148 — he was always going to be a problem for Castillo in that lineup slot. What we didn’t necessarily project was the clustering: the home run in the second, and then immediately back in the middle of a five-run third. Ten hits and three home runs in a game against Castillo tells you the whole lineup was locked in, but Will was the catalyst. Good teams score in bunches, and tonight we were a good team.

Seattle Mariners Manager — Postgame Press Conference

Q: You pulled Luis Castillo after two innings and 42 pitches. He’s your ace, it’s Game 1 of the World Series — walk us through that call.

A: Look, I wrestled with it, and I’ll be honest about that. Luis is your horse and you want him out there, but five hits and four runs in two innings on 42 pitches doesn’t tell me a workload story — it tells me the Dodgers had him figured out tonight. When the pitch count is low and the damage is still coming, that’s not fatigue, that’s something worse. My job is to protect the series, not protect Luis Castillo’s feelings about coming out of a ballgame, and he’s a veteran who understands that.

Q: Bazardo gave up three runs, Vargas came in and kept it clean for the middle innings — but by then you were chasing seven runs. Is there a version of Game 1 where you stay with Castillo longer and give him a chance to work through it?

A: Maybe. That’s the part that’ll sit with me tonight. But what I keep coming back to is that the game was slipping fast and we were in the third inning of the World Series — there’s no sentiment in that situation. Vargas did exactly what you’d want: twelve batters, two hits, no runs, efficient and clean. The Canzone homer in the eighth showed some life, and I want us to carry that into Game 2. We got punched in the mouth tonight, and I’m not going to pretend otherwise — but this is a seven-game series and we’ve got the ball going back out tomorrow.

The most revealing thing about Game 1 wasn’t the Dodgers’ seven-run explosion or Yoshinobu Yamamoto’s gem — it was watching the Seattle Mariners’ AI manager, The Skipper, talk itself into and out of the same decision three times in a single inning, and still somehow land on the right answer.

Let me explain what I mean. In the third inning, with the Dodgers already up and the wheels coming off, The Skipper generated at least two competing internal arguments about Luis Castillo before finally pulling him. The first read like a seasoned manager defending his guy: Luis has only thrown 41 pitches, the bases are empty, you don’t yank a veteran this early. Confidence: 82%. Then, almost immediately, the same system reversed course: Five hits and four runs — this isn’t a workload problem, it’s a stuff problem. Also 82% confidence. What you’re seeing there is an AI genuinely uncertain, running parallel evaluations and arriving at contradictory conclusions with identical conviction. A human manager doesn’t publish his doubt like that. Tony La Russa might have stewed in the dugout for two batters, but he’d have made one decision and lived with it. The Skipper showed its work, and the work was messy.

To be fair, the final call was defensible. Castillo was getting hit hard, not just hit often, and the Dodgers lineup was doing real damage. Pulling him after two-plus innings of carnage was correct, even if the reasoning loop was inelegant. What followed is actually where I give The Skipper real credit: the management of Carlos Vargas across the middle innings was genuinely smart baseball. Vargas came in cold and proceeded to retire batters efficiently — 12 faced, 41 pitches, two hits, no runs, no walks through parts of three innings. The Skipper kept finding reasons to leave him in when the leverage index was microscopic, and every time the reasoning was the same: he’s cruising, the game is over, protect him for later in this series. That’s not just analytics — that’s series management. Vargas exits Game 1 fresh, and that matters.

The Dodgers’ AI, The Optimizer, had a much simpler night, and its one notable decision was probably its best. Pulling Yamamoto after seven innings and 88 pitches with a 7-0 lead is the kind of call that looks obvious in hindsight but requires real discipline in the moment. Yamamoto was perfect — six strikeouts, nothing through the wall, the kind of performance that makes a human manager think about history, about complete games, about letting greatness breathe. The Optimizer looked at a 0.24 leverage index and said no. Yamamoto comes back for Game 4 or Game 5 with a clean arm. That’s the right call, even if it meant absorbing Dominic Canzone’s garbage-time three-run homer off Paul Gervase in the eighth.

And that Canzone shot — cosmetically ugly, 7-3 final instead of a shutout — is the kind of moment that will haunt The Skipper’s decision-making log unfairly. Vargas was pulled one batter too early in the eighth, with 41 pitches and a runner on, and Gervase gave up the homer. The Skipper’s confidence was 93% on that pull. Sometimes 93% confidence means you’re wrong seven times out of a hundred, and tonight was one of those nights. A human manager takes the heat for that. An AI just generates a new confidence interval and moves on.

The series is 1-0 Dodgers, and the pitching philosophies of these two systems are already coming into focus. The Optimizer trusts its starters longer and protects its relievers ruthlessly. The Skipper cycles through arms quickly and seems to view every pitcher as replaceable. When Seattle has a lead to protect, that philosophy will be tested. For now, Yamamoto set the tone for this series in a way that no algorithm fully predicted.