You don’t necessarily need fancy numbers to know that Yordan Alvarez had an incredibly valuable game in Houston’s stunning Game 1 win, because it doesn’t exactly require a lot of science to say that “going 3-for-5 with a walk-off home run to help your club come back from a 7-3 deficit” is a very good thing to do.

“I think it's one of the most special moments that I've had in my career, having [my parents] there, and even for just the city of Houston,” Alvarez said, and we could hardly disagree.

But what if we told you that we had those fancy numbers, and they say this was the most valuable postseason game – and moment – a position player has ever had?

And what if we told you, furthermore, that those numbers don’t even capture the entirety of what Alvarez just did?

It wasn’t just a memorable game, or a dominant one. It was a historic one.

The most impactful play ever?

When Alvarez stepped to the plate in the ninth inning, Seattle’s win probability was 91%. That’s based on the history of road teams who were ahead by two runs with two outs and two on in the ninth inning, as the Mariners were. It’s not like teams in those situations never blow a lead; it happens, sometimes, if rarely. That’s why it’s 91% and not 100%.

If Seattle's odds were 91% when the pitch left Robbie Ray's hand, then by the time Alvarez’s blast landed 438 feet away, their odds of winning were 0%, because the game was over. Houston was at 100% – again, the game was over! – up from 9%. Just look at the chart. You get the idea. Look at that absolute cliff at the end.

The way win probability works, Alvarez gets credit for the 91%. If you go pull up the list of the most important postseason plays in history in terms of winning that specific game … ladies and gentlemen, we have a new No. 1.

+91% – Alvarez home run, ALDS Game 1, 2022
+87% – Kirk Gibson home run, WS Game 1, 1988
+83% – Jimmy Rollins double, NLCS Game 4, 2009
+83% – Brett Phillips single, WS Game 4, 2020
+83% – Cookie Lavagetto double, WS Game 7, 1947

Every other player on this list had their team down by one run with two outs, not two runs; every other team that had odds so low came back with multiple plays, not one. As MLB.com’s Sarah Langs noted, there had been only four walk-off homers when trailing in postseason history, and only two of those four came with two outs, and only Alvarez’s also came while behind multiple runs. He now stands alone in history.

(We should note that the first game of a division series doesn’t exactly compare to, say, walking off the seventh game of a World Series. There’s a different metric for that, one we have explored in the past. This view is just about winning the specific game you’re in.)

• Postseason ticket information

That's what happens when you blast a ball at 116.7 mph off the bat, as Alvarez did, which is now the fourth-hardest hit ball for a walk-off homer (regular season included) since 2015. The ball was projected to travel nearly 100 feet beyond the short fence in Houston's right field.

At contact, he had the sweet spot of the bat moving at a pretty-much-elite level of 94.1 mph; as you can see here, he caught it out front, and squared it up nearly perfectly. None of that is factored in to the absolute value of the walk-off; Houston still wins the game even if it's a cheap shot into the Crawford Boxes. But it was hardly that, was it? Alvarez earned every bit of this one.

But to focus just on the home run risks ignoring something else, too. Alvarez didn’t just have the most impactful play of the game, he had the second-most impactful play, too, on his third-inning double that cut the Seattle lead in half from 4-0 to 4-2. That added 15% to Houston’s chances of winning, doubling it from 15% to 30%. (It would later go down, obviously, as the situation became more dire.)

When you have not only the most impactful in-game moment in postseason history, but also a second very big hit, plus a third hit that mostly canceled out the two outs he made, you start adding those plate appearances together. The result of that? Prepare for another list with Alvarez at the top.

The most valuable postseason game ever?

Again: Just by hitters – sorry Don Larsen – and without the context of the round and game. The question being asked here is just how much did you do to help your team win this particular game, in the most important moments?

With a win probability added of +105.2% – and more on how that is possible in a second – it’s now the number one most impactful game in postseason history. You could say no hitter ever did more to help his team win, and you wouldn’t be wrong.

+105% – Alvarez, ALDS Game 1, 2022
+96% – David Freese, WS Game 6, 2011
+87% – Gibson, WS Game 1, 1988
+85% – Steve Garvey, NLCS Game 4, 1984

But wait, more than 100%? That’s impossible; by definition that is the most anyone can give. That’s a little about how win probability can go up and down as a game goes along, and a lot about how many other Astros (notably starter Justin Verlander, who allowed six runs in four innings, and batters Jose Altuve and Trey Mancini, who combined to go 0-for-9 with a walk) were a net negative towards Houston winning this game. Alvarez didn’t just have to perform his own heroics. He had to overcome the hole the Astros placed themselves in to get there.

Don’t forget that outfield throw.

There’s one more thing, though. Win probability, as currently constructed, considers just a hitter’s performance at the plate. It doesn’t include defense. Alvarez is generally known as a designated hitter, but in the fourth inning, he provided a bit of defense, and then some. This won’t show up in any win probability metrics, but his walk-off might not have been possible without …

… this incredible play in the fourth inning.

That one came with the Astros already down 6-2; another run wouldn’t have just put Houston down five runs, it would have likely left batter Eugenio Suárez in scoring position with postseason hero Cal Raleigh coming to the plate. It might have changed the way Dusty Baker chose to deploy his relievers; it definitely would have changed the energy inside Minute Maid Park.

When Alvarez got to the ball, he was 197 feet from home – Ty France, the base runner, had just rounded third and still had nearly 80 feet to go – and he uncorked a 93.6 mph throw that was the third-hardest he’s had in his Major League career.

Alvarez isn’t particularly fast, just 28th percentile in Sprint Speed. Nor is he a rangy outfielder, with a negative-5 mark in Outs Above Average that illustrates why he spends more of his time at DH than he does in left field. But with Jose Siri traded to the Rays, Alvarez has the strongest arm of the remaining Houston outfielders, one for which he does not get enough credit.

Think about it this way: In 467 2/3 innings in the outfield this year, or 111th-most, Alvarez had seven assists, or tied for 23rd. That’s a little about respect or lack of it, because players tend not to run on arms they fear. But the better defensive metrics account for this, giving credit not only for runners thrown out but also for attempts not even made. By the arm component of Defensive Runs Saved, Alvarez’s arm was tied for the fifth best among outfielders this year. By a forthcoming Statcast metric, he was the second best on a per-opportunity basis behind Oswaldo Cabrera, and, similarly, fifth best overall.

Alvarez is known for his bat more than his fielding, quite understandably; only Aaron Judge out-hit him this year. But in a game where he just had the most impactful hit to win a game in postseason history, where he may have just had the most impactful game overall of any hitter in postseason history, there was more to it than just that. There was the throw that saved a run. There was the throw that helped keep the game close enough to even allow for the walk-off we’ll never forget.