HOUSTON — If this were the American League Championship Series of exactly 20 years ago, Red Sox manager Jimy Williams would have said “Manager’s decision” and that would’ve been the end of it.

Aaron Boone presented his tabbing of Masahiro Tanaka as his American League Championship Series Game 1 starter with more diplomacy, yet left us similarly unenlightened.

“I felt like it was a good decision,” the Yankees’ manager said Friday at Minute Maid Park. “Tough one to be made, but similar to the Division Series, where I was going back and forth a lot. Just felt like Masa here in Game 1 is the way I wanted to go in the end.”

In reality, it presents no great mystery why the Yankees went with Tanaka, who started and won AL Division Series Game 2. Unfortunately for the Yankees, it’s not because Tanaka has performed amazing work against the Astros’ potent offense. He hasn’t. Astros regulars George Springer (.976 OPS), Michael Brantley (.922), Alex Bregman (.912) and Jose Altuve (.828) all have done their share of damage against Tanaka.

Almost none of that damage, however, came two years ago this very week, when Tanaka compiled a 1.38 ERA in two starts totaling 13 innings as he started Games 1 and 5 of the ALCS just as he’s slated to do this week, his first assignment in Houston and his second in The Bronx. Slotting him here reflects the faith the Yankees hold in Tanaka, who owns a career postseason ERA of 1.54.

“One thing I can say is that we’ve been here in 2017,” Tanaka said through an interpreter. “We know what it’s like in here. So I think that experience will definitely help going into the game.”

This assignment, with James Paxton set for Game 2, Luis Severino for Game 3 and a formula to be determined for Game 4, also affords Tanaka one home game. He tallied a 3.10 ERA at Yankee Stadium this season as opposed to a 6.10 ERA on the road and for his career holds a 3.36-to-4.15 edge at home.

“As far as facing the Houston lineup, obviously it’s going to be a challenge,” Tanaka said. “But you try not to do anything sort of different going into the game. You prepare for it. You make your plans, and basically you go out there and execute.”

The Yankees trust Tanaka to do just that. He has yet to let them down this time of year.