You heard it in the middle innings and then again in the eighth when the Mets were coming back against the San Diego bullpen just the way they had on Monday night when 8-4 the wrong way became a 9-8 walk-off for the home team.
This time a 4-2 hole turned into a 5-4 victory after Angel Pagan knocked one out of the park to lead off the inning, Nick Evans came off the bench to crack a sacrifice fly to tie it and Ruben Tejada worked a full count, bases-loaded walk to bring home David Wright with run that would win it.
And what you heard was a sound from yesteryear, a sound made famous in the old place across the parking lot but one that had largely been lost to ennui, disgust and distracting exhortations on the scoreboard over the last three seasons.
It was, quite simply, a spontaneous chant of “Let’s Go Mets . . . Let’s Go Mets . . . Let’s Go Mets . . .,” and it came out of the stands at CitiField as it had on Monday, as it had during Saturday night’s victory over the Braves.
You know what that tells you?
The fans haven’t given up any more than their team has.
You know what else that tells you?
These fans like the Mets.
They really like them.
The lineup is loaded with the equivalent of seat-fillers, guys who are taking the projected regulars’ spots in the lineup much as individuals are hired at televised award shows like the Oscars to fill the seats of stars who vacate them when other duties call.
Guys like Tejada, here because Jose Reyes, the NL’s leading hitter at .336, isn’t. Guys like Evans, here because Daniel Murphy, the NL’s fifth-leading hitter at .320, isn’t.
But these Mets are turning woe into whoa! They are turning heads, refusing to go away no matter how many of them have left and gone away, hey, hey, hey, through trades or trips to the disabled list.
“I don’t know why anyone would have thought our team would throw in the towel or give up,” Justin Turner told The Post. “That’s kind of a slap in the face to the guys who are here.
“Players get traded and players get hurt. That’s part of baseball. We’ve got 25 guys in here busting their butts to try to win games and who believe in ourselves and our team.”
The twin tracks of the present and future are converging. This isn’t a team stocked with embittered veterans playing out the string. The more the young guys contribute, the more the Mets win, the more the young guys solidify themselves.
“The young guys have a hunger to open people’s eyes and prove they belong,” Pagan told The Post. “The type of attitude we have is to take adversity and turn it into opportunity.
“We’ve lost some key players, but we still have a job to do and that job is to win games. One of the keys to our success is being a hungry team.”
The combination of hunger and commitment to doing things the right way — such as cleanup hitter Lucas Duda successfully laying down his first big league bunt to move the tying run to third and the winning run to second in the eighth — has made life a little easier for manager Terry Collins.
“I’ve never had a team where so many guys are playing for a position for next year as we have here,” Collins said. “I wish I could tell you how many times I’ve seen good [Triple-A] players who were dying for the opportunity to play in the big leagues, just dying for it, and never really got the chance to prove themselves.
“Here, these guys have the opportunity, and they’re stepping up.”
The Mets have stepped up to 58-57. Young guys are making their mark.
“If you have success as a team, you’re going to be successful as individuals,” Turner said. “If a team wins, a lot of people get rewarded.”
Including the fans who are ready to chant, “Let’s Go Mets” when they like what they see.
larry.brooks@nypost.com