HOUSTON -- Part of Masahiro Tanaka's legacy with the Yankees is that he’s money in October. How do you define that? By putting him in the conversation with, oh, Mariano Rivera.

With the stage large and the spotlight bright, Tanaka has been at his best, and that’s ultimately how Yankees are judged. That was true again on Saturday night in Game 1 of the American League Championship Series, as he threw six innings of one-hit baseball in a 7-0 victory over the Astros at Minute Maid Park.

“That's probably the best that we've seen him in a small sample to execute his game plan, his pitches, his tempo,” Astros manager AJ Hinch said. “Just about everything was working for him. He was just really, really good tonight.”

That the Yankees won 103 games with a rotation that was a work in progress is one of many remarkable chapters of a remarkable year. No one could question any other part of their team.

Their offense led the Majors in runs, and their bullpen was as good as almost any. Now at the most important time of the year, the Yanks suddenly have starting pitching. This is what they haven’t had most of this season, and this could be the thing that makes them unbeatable.

In four postseason games -- all victories -- Yankees starters have a 1.83 ERA. Manager Aaron Boone is cautious with their workload, but he can afford to do that because his bullpen is so good. He removed Tanaka after just 68 pitches, trusting the ‘pen to nail down the final nine outs.

The Yankees evolved in all sorts of ways this season, but in September, it was the rotation that got better. Yanks starters led the AL with a 2.92 ERA in September. ALCS Game 2 starter James Paxton had a 2.51 ERA over the final two months of the season, and right-hander Luis Severino, who’ll go in Game 3, is healthy for the first time all year.

In seven postseason starts, including Saturday’s, Tanaka’s postseason ERA is 1.32 over 41 innings, and he has never allowed more than two earned runs in any start. Of all the Yankees who’ve pitched 40 postseason innings, only Rivera’s 0.70 ERA is better. As Yanks legacies go, it doesn’t get better than that.

“I think he does a good job, clearly, of not necessarily making more of the moment,” Boone said. “But really I think the guys that can lock in and are in command of their body and their mechanics have a chance to be better when the stakes are high. And he's very good at that.”

Tanaka is the first pitcher in history to allow two runs or fewer in his first seven postseason starts. Until Saturday, Tanaka and -- wait for it -- Sandy Koufax had been tied with six postseason starts of two earned runs or fewer.

“You can tell early on that [Tanaka] was locked in,” Yankees center fielder Brett Gardner said. “When he was able to throw his offspeed stuff for strikes and get ahead and keep guys off balance, he’s as good as it gets.”

Game 1 was one the Yanks probably had to win because the Astros have aces Justin Verlander and Gerrit Cole lined up to pitch four of the final six games, if the series goes that far.

Tanaka was in complete control, teasing the Astros with an assortment of fastballs and offspeed stuff. To focus on his velocity -- 89-91 mph -- is to miss what makes him so good.

“He just missed barrels,” Houston third baseman Alex Bregman said. “He’s just going to float the line between balls and strikes the whole game.”

The Astros lined into a couple of costly double plays that helped Tanaka out. But throughout the game, he reminded Houston how much he understands the art of changing speeds and throwing pitches on the edge of the plate, pitches that aren’t really strikes and aren’t really balls, either. These are pitches that test both the patience and the nerves.

In six innings against Tanaka, the Astros had a walk and a single, didn’t get a runner into scoring position and hit only two balls out of the infield. Tanaka struggled at times this season, but in two postseason starts, including one in the AL Division Series against the Twins, he has allowed one earned run in 11 innings. As for considering the legacy part of the deal, he’s not there yet.

“Yeah, obviously the numbers are there, and I guess I'm flattered,” Tanaka said. “But the happiest thing for me is us being able to get the W. And knowing that you went out there and you gave everything you had, that's the feeling that you're looking for. And so that's kind of where I'm at with that.”