PORT ST. LUCIE, Fla. — Antonio Bastardo is one serious man.

And that is exactly the attitude the Mets need to clean up their eighth-inning bullpen woes.

Bastardo does not want manager Terry Collins to have to extend closer Jeurys Familia by bringing him in for four- or five-out saves. The lefty said he will handle it — whether he is facing left-handed hitters or right-handed hitters.

That eighth inning belongs to him.

“I know the Mets needed help and that is why I signed here,’’ Bastardo, 30, told The Post on Wednesday, his first interview since signing with the Mets as a free agent for two years, $12 million.

“The Mets have a great team, with great, great young arms. We just have to make sure we stay focused and hopefully this year or next year we can win the World Series,’’ Bastardo said.

“I want to make it so Familia is fresh in the ninth inning. Four outs is a lot of work for the closer. You want him fresh for that winning situation in the ninth.’’

Yes, Bastardo is all in, and the Mets will use him in the most crucial of situations against the best of hitters and in the NL East, which means plenty of confrontations against Bryce Harper and Freddie Freeman.

Harper is 2-for-12 lifetime with seven strikeouts against Bastardo while Freeman, simply a Mets killer, is 0-for-19 with nine strikeouts vs. Bastardo. In the NL Central, where the Cubs are expected to excel and the Mets have a good chance of facing them again in the postseason, new Cub Jason Heyward is 2-for-19 with seven strikeouts vs. Bastardo. None of those hitters has homered against Bastardo.

“I know they are good hitters so I go right after them,” Bastardo said. “I challenge them inside, you can’t be afraid to do that. I try not to miss because if I miss my spot, they can crush you.’’

Bastardo was 4-1 with a 2.98 ERA with the Pirates last season. Lefties hit .138 against him, while righties didn’t exactly flourish either, hitting .210 off Bastardo.

His well-placed fastball sets up his breaking ball.

“I’m totally fine facing lefties or righties,’’ Bastardo said. “I feel the more I pitch, the better I get. During the season, you never know what situation you can face.’’

Bastardo showed his seriousness by showing up early for pre-camp, and all this week has taken young lefty Steven Matz under his wing. They throw together, do sprints together, with the veteran Bastardo offering some timely tips.

“He’s stoic at times, but that’s his personality,’’ said one National League scout. “I already told the Mets people they got a good one. They just have to be careful not to wear him out because he will always take the ball and he gets in trouble when his velocity dips.’’

Then the command is lost, too.

Bastardo already has a strong relationship with Familia, a fellow native of the Dominican Republic.

“A few years ago in Winter Ball, I helped him,” Bastardo said. “He was having a little bit of trouble with the fastball command and I told him what he was doing wrong and he got on fire after that. His stuff is amazing, 98 with sink, and now he throws a splitter. At the time he was not a closer and I told him don’t be afraid to take that job as closer, go for it.’’

Familia is outgoing, always with a smile, but Bastardo has a much different makeup.

“You are not going to see that on me,’’ he said.

Bastardo said he likes to spend his time away from the field with his wife and their 8-month-old son.

“I really don’t have time for anything else,’’ he said, almost cracking a smile.

Bastardo is here to do a big job. The Mets need his no-nonsense approach as much as his left arm and experience.