CINCINNATI — Demand more. Expect more.

That should be the Mets’ mantra in 2020.

Too often the Mets and their fans settle for the phrase “meaningful September games.’’

How about demanding meaningful October games?

This was a season that should have been so much more, especially with the weakened competition in the National League and key injuries that hit the Cubs and Brewers.

Instead, the Mets (81-74) remain four games back of the Brewers in the loss column with seven to play even after Sunday’s 6-3 victory over Trevor Bauer and the fundamentally challenged Reds at Great American Ball Park in what could have been Mickey Callaway’s last road game as Mets manager.

Think of it. The Mets’ rotation stayed healthy the entire season and yet, barring a miracle, the team will not even break down the wild-card door. Jacob deGrom, Zack Wheeler, Noah Syndergaard, Steven Matz and the tandem of Jason Vargas and Marcus Stroman have been there every five days to make their starts.

That alone should have been a recipe of success to make the playoffs.

Tack on Pete Alonso’s Amazin’ rookie season and you should have really had something going. With his first-inning double, Alonso became the first rookie in major league history to post a 30-50 season — 30 doubles and 50 home runs.

Add Jeff McNeil’s huge season as well and that should have been the offensive nucleus to a playoff season.

Because of the Mets’ strong second half, there are some who believe they are moving toward greater accomplishments in 2020. It is that kind of thinking that enables the Wilpons to get away with not making the extra effort in the winter to build a team that is basically guaranteed the postseason, kind of what the Yankees did this past winter with the major parts they added.

Here is another issue. Something that has been overlooked by those who live in Mets Fantasyland. Against the good teams, the Mets struggle.

The numbers are startling.

Against the likes of the Dodgers, Braves and Cards — the three division leaders in the NL — the Mets are a combined 9-21. If you throw in some other just OK teams like the Brewers, Cubs and Phillies, the Mets are a combined 19-43.

The only decent NL team they have a good record against is the Nationals, who often can’t get out of their own way, losing a vital game to the lowly Marlins on Sunday.

The Mets have to demand more than general manager Brodie Van Wagenen’s “come get us.’’

After the Mets’ 40-50 start, the words changed to “they came and got us.’’

That pitching staff could look a lot different next year, because Wheeler is a free agent and perhaps Syndergaard will be dealt away this winter.

The best approach is what I call the Alonso Approach, and the Mets need to have this mindset going forward.

When I told Alonso no other rookie had hit the 30-50 mark, Alonso smiled and said he thought Aaron Judge had compiled 30 doubles in 2017 when he hit 52 home runs.

“That’s really cool, I didn’t know that, that’s awesome,’’ Alonso said.

“For me it would mean a lot to finish strong and keep pushing,’’ Alonso said. “I like to do everything 100 percent. I’d like to end the year how I’ve been all throughout [the year]. I don’t want to have a sour taste in my mouth, knowing that I could do more and keep grinding it out every single day and keep doing what I can.’’

That must be the Mets’ mindset from Day 1 in the future — 100 percent.

Maybe that team-wide approach would have kept the Mets from their 40-50 record at the All-Star break. Since then, they have gone 41-24, guaranteeing them only their third non-losing season in the past 11 years.

Barring a meltdown miracle from the Brewers or Nats this final week, the overriding feeling of this season will be that this Mets team should have done more and should have found its way into at the least the NL wild-card game.

This rose did not bloom. A few long-shot September games are not fulfilling.

There must be more in 2020.