Kansas City, Mo ? Believing in the Royals isn’t a matter of faith anymore. It’s more about the math.

Just two days into summer, Kansas City — a team that hasn’t been a pennant contender in nearly a decade — is just a game behind division-leading Minnesota in the AL Central. And while there are 90 games left on the schedule, only 25 are against teams with a winning record.

“We’re fighting,” said manager Tony Pena, who started the talk about believing in Kansas City’s chances during spring training. “We’re just fighting. We’re going to find a way because when you’re a winner, you find a way. I believe that, and I want them to believe that.

“In the past, I think they had a hard time believing they could win.”

After starting the season a shocking 16-3, the Royals tumbled below .500 before winning 10 of their last 15 in a stretch against the Rockies, Diamondbacks, Giants, Twins and Cardinals.

“This last two weeks proved more about our team than the 16-3 start,” Royals outfielder Raul Ibanez said. “No doubt about it — especially since we went in the tank for a while.

“By coming out of it, against good teams, we proved a lot about this team.”

The 2-1 series victory over the weekend against St. Louis — a team that was expected to reach the postseason — capped a vicious stretch of 30 games, 27 against teams that won 92 games or more in 2002. Despite dropping 12 of 15 at one point, and suffering through injuries to four of the club’s starting pitchers, Kansas City emerged 38-34 and just one game out of first place.

“Everybody knew we were going through a rough stretch there,” general manager Allard Baird said, “but I think everybody saw a light at the end of the tunnel.”

But to get back to the postseason for the first time since winning the 1985 World Series, the Royals will need to — at a minimum — improve a bullpen that statistically is the worst in baseball.

But Pena isn’t concerned about that — or much of anything else.

“We don’t have to worry about anything except worry about ourselves and what we’re capable of doing,” he said. “Our whole staff preaches that and the veteran guys have stepped in and said it’s true.

“Whenever you want something, you have to go after it. That’s what we’re doing. We want to be in the playoffs and we’re going after that.”