GROVE CITY - When Mike Johnson glances at the scoreboard and sees a number that is too large for the opposing team, he snarls.

To Johnson, though, any number greater than zero is too large.

"Anytime they score, it's too many points," Johnson said.

Lucky for Johnson, the Grove City High School boys basketball team is stingy with the points it surrenders these days.

Defense has been the not-so-best kept secret of the Eagles success this season.

Grove City, sitting at 19-5 heading into its District 10 Class AAA semifinal game against Erie Strong Vincent at 7:30 p.m. today at Meadville, has given up just a shade more than 45 points per game this season.

"We take so much pride in it," said guard Kevin Persch. "Our rotation is the key to what we do. We just have five guys on the court busting their butts. I think when we are all doing that, we are as good as any defense in the state."

Throw out a couple of 70-plus scoring games by Class AAAA power George Junior Republic, and the Eagles are giving up just 42 points per game.

The Eagles have held rival Slippery Rock to 25 points and gave up just 17 points against a Keystone Charter team that went into that late-January game with a .500 record.

After the loss to Grove City, Slippery Rock coach Chris Burtch marveled at the newest incarnation of the Eagles' defense.

"Grove City always has a good defense," Burtch said. "But this may be their best defense I've ever seen."

The motor that makes the Grove City defense run is its relentlessness.

Always moving, the Eagles swarm to the ball - particularly when they are trapping - forcing turnovers that result in easy points.

Johnson is particularly adept at getting quick steals and points. The 6-foot-4 senior uses his long arms to disrupt passing lanes and his strength to rip the ball out of opponents' hands as he did twice in a 54-41 win over Corry last Thursday in the first round of the playoffs.

"Mike is so rangy off the point, he really disrupts things," Persch said.

Grove City plays mostly man-to-man defense, but sometimes throws in a 1-2-2 zone to further complicate matters for the opponent.

The switch to the zone baffled Corry and helped the Eagles to a 12-0 run to start the second half that put the game away.

"You can see them get frustrated," Johnson said of the opponent when the Eagles' defense is clicking. "They are taking shots they are not used to taking. They are forcing things. That plays right into our hands."

Persch is in many ways the general of the defensive force. Always vocal, he directs traffic and directs some pointed criticism when things are not running as smoothly as it should.

"Kevin tries to keep us motivated," Johnson said, smiling.

"Yeah, I like to get after the guys," Persch added. "You have to get up to play defense."

Grove City coach Don Fee also has a deep bench to draw from, which helps the Eagles maintain their frenetic pace the entire 32 minutes.

"We have a bunch of guys we can bring in," Persch said. "That gives so much relief to us to have those guys who can come in and play just as good defense."

If the points start piling up against Grove City tonight - say more than 10 points in the first quarter - watch out.

Johnson just may snarl.

"When we look at that score," Johnson said, "it motivates us."