SAN FRANCISCO – Billy Wagner called his teammates on the carpet yesterday, saying the Mets were big-time underachievers in the first half, even though they are in first place at the All-Star break.

“We underachieved,” Wagner told The Post during the All-Star National League interview session. “There was no consistency in our offense. There was no consistency in our bullpen. And we have the talent on both sides to probably be twice as good as what we played.”

The Mets have to play the second half with more focus and Wagner wants that to begin immediately. They own just a two-game lead over the Braves.

Carlos Beltran agreed to an extent, saying, “We learned we have a pretty good team. Even though we went through a lot of ups and downs we are still in first place. We didn’t play the way we know we can play but we’re still in first place. With a lot of guys coming back we can play a lot better.”

Wagner wants to see the Mets pick up their game right from the start of the second half. They open up at home against the Reds. The Mets finished the All-Star break at 48-39.

The lesson learned in the first half, Wagner said, “Was that we can’t play this inconsistently going into the second half. And we can’t worry about our injuries. We’ve got more talent than most teams and we have to go out there and perform.”

In other words, the Mets don’t need to be making excuses. They just need to go out and win.