PORT ST. LUCIE, Fla. -- So, Robinson Cano, how are Mets fans going to like their new closer, Edwin Diaz?

“Oh man,” Cano said.

Yeah, oh man. To a shaky Mets bullpen comes arguably baseball’s surest thing in the ninth inning, and Cano saw the emergence firsthand while the two of them were teammates in Seattle.

“It’s the way he improved so fast,” Cano said. “He’d been a starter in the Minors, and when they made him a reliever and sent him to the big leagues, he was amazing.”

On the other side of the Mets spring clubhouse, the 2018 National League Cy Young Award winner has also given the matter some thought.

“You come out of a game,” Jacob deGrom said, “and you hand the ball over to any of these guys we’ve got in the ‘pen, you’re going to feel comfortable that they’re going to keep a lead.”

On Sunday afternoon, the Mets used four of their primary bullpen pieces in a 9-1 victory over the Cardinals. Robert Gsellman, Jeurys Familia, Justin Wilson and Diaz worked 3 2/3 innings, and Diaz allowed the only run -- a Dylan Carlson home run in the eighth.

In new general manager Brodie Van Wagenen’s reshaping of the Mets, his goal was to construct a club that wouldn’t waste what might be baseball’s best rotation.

He added Cano to the middle of an offense that was 23rd in runs, 21st in home runs and 24th in OPS. And to a bullpen that was 28th in the Majors in ERA, Van Wagenen added four significant arms, beginning with Diaz, who came from the Mariners in the seven-player deal that brought Cano back to New York.

Also, Van Wagenen signed three free agents who figure to be part of the Opening Day roster: Familia, Wilson and lefty Luis Avilan.

“We’ve got guys other teams don’t want to face,” deGrom said. “You know that when you’re giving them the ball, and they know that on the other side.”

Diaz, 25, is the key. He led the Majors with 57 saves last season while averaging an impressive 15.2 strikeouts per nine innings. He allowed less than a single baserunner per inning (0.79 WHIP) and was eighth in American League Cy Young Award voting.

“I think as a team when you have a bullpen like that, as a position player, you want to make every play,” Cano said. "You want to score early and give your starter a chance. You want to take away the pressure of a close game and give him some runs.”

As for Diaz, he said the trade caught him by surprise, but that he has felt the excitement Mets fans -- and the Mets themselves -- are feeling about 2019.

“We know this is a great team,” Diaz said. “We can make the playoffs this year. Robby [Cano] played a lot of years in New York. All the moves the team made, they want to win. We’re ready for that. This rotation is one of the best in baseball, and I think we’ll have a lot of chances.”