The Seattle Mariners are about to learn just how good they are.

It’s one thing to pull off all these extra-innings dramatics and one-run victories (two things they lead the majors in) against these American League Central teams and the bottom of the American League West.

It’s another to keep that up for the rest of this month.The Mariners leave Houston for a four-game series in Tampa Bay, and then things get real interesting: Seven games against the Los Angeles Angels and the Boston Red Sox at home before six games on the road against the New York Yankees and the Red Sox.

But if Tuesday’s 7-1 bashing of the Astros was any indication, maybe those teams should fear the Mariners — not the other way around.

“To be on a 100-plus win pace, I would be lying to you if I told you that coming into the season I thought we were a 103-win team,” Dipoto said in his weekly radio segment on 710-AM radio. The Mariners, entering Wednesday, were on pace to finish the season with that many wins (which would be their second-most wins in any season in team history, trailing the 116-win season of 2001).

“But we did think we were a playoff contender.”

Granted, it is still early.

Mariners manager Scott Servais warned as the team entered Houston to face the reigning World Series champs that maybe the world shouldn’t take a world of significance out of this series. Wait until they face each other in the middle of September for that.

Still, when the Mariners posted their most lopsided win since early May, Servais said Tuesday it was a statement victory.

They’d done this through pitching. Who would have thought journeyman left-hander Wade LeBlanc would be performing like a Jacob deGrom or Justin Verlander? His 1.62 earned-run average entering Wednesday over his past seven appearances (six starts) was tied for the fifth lowest in the majors behind the Mets’ deGrom (0.67), Astros’ Verlander (1.13), Braves’ Sean Newcomb (1.32) and teammate James Paxton (1.60).

Since May 16 (one day after Robinson Cano was hit with an 80-game suspension) the Mariners’ starting pitchers have going 9-1 with a 2.09 ERA. Mariners starters lead the majors in ERA in that span.

“We thought all along that our pitching was better than people were giving it credit for,” Dipoto said.

But the critics will point to the level of competition and narrow margins of victory. Entering Wednesday, the Mariners trailed just the Red Sox and Yankees in wins, but 12 teams in the majors had better marks than the Mariners’ plus-23 run differential.

That’s because the Mariners have 18 one-run victories, they are 6-0 in extra-innings, they’ve won 12 games when scoring three runs or fewer. They’ve had plenty of timely pitching and timely hitting.

“A lot of people say, ‘Oh, you can’t sustain that. It will catch up with you …’ I don’t know,” Servais said recently. “I’m not worried about it. I’m worried about tomorrow’s game and that’s how we’re looking at it. We’ll find out tomorrow how to win.”

Dipoto pointed to their chemistry for being able to prevail in close games.

“The internal build with this team — you got a very good vibe about this group, about the way they are wired,” Dipoto said. “The internal build on this club is different even than the past three years.

“They enjoy one another and you could see that come together in the spring. It was evident on opening night (against the Cleveland Indians) when they had to grind against a team that had won more than anybody else in the American League. We found a way to win a game that in the recent course of Mariners history we would have found a way to lose.

“That has been the trademark of this team. They find ways to win games that historically would have found ways to lose.”