Greencastle (14-2) took advantage of two JB errors to score four runs in the first. With one out, Roxanne DeWalt reached when Rockets first baseman Jess Long failed to catch the throw from pitcher Laken Beers, resulting in a two-base error. Brittany Main followed with a bloop single to right to score DeWalt.
Main went to second on a wild pitch and scored on Kayla Pond's two-out single to center. Amanda Ritchey followed with an infield single before Casey Walburn singled to right to drive in Pond, and right fielder Sara Dykes let the ball get past her, allowing Ritchey to race home.
"(The first inning) destroyed us," Rockets coach Ken Kauffman said. "I don't think we got down on ourselves, but we made a key mistake. We could have been out of the inning without giving up a run, and it went downhill from there."
Megan McCracken tripled down the left-field line and scored on a wild pitch to give JB (10-3) its only run in the second inning.
Christman, who struck out against Beers in the first inning, blasted a two-out drive over center fielder Beth Hawbaker's head in the second to break the game wide open at 7-1.
"It felt so amazing just to hit that ball," said Christman, who added a double and the game-ending RBI single later. "There have only been a couple of pitchers to strike me out all season, so I really wanted to get a hit off her."
"That was a key at-bat, and I knew she was going to put the ball in play," Blue Devils coach Jamie Richardson said. "She never strikes out, and she had an attitude after that."
Signore - Greencastle's speedy leadoff hitter who usually makes her living at the plate with bunts and slaps - launched a rocket to right center in the third for her first home run of the year, making it 10-1. It was her second extra-base hit of the season.
"Coach never lets me run when I'm on the bases," said Signore, who often is replaced by a courtesy runner on the bases. "He was telling me to stop at third, and I was like, 'No!' I wanted to run home, and I think he was playing mind games with me."
"No, no, no ... I told her to take her time," Richardson said. "I knew they had no play. I didn't want her to do anything crazy."
Greencastle finished off JB in the fourth, with its six runs coming on six hits and three Rockets errors. Rachel Statler had an RBI single and Signore drove in another with a groundout.
"I'm just proud of our kids," Richardson said. "We did lose to them the last time, and since then we've circled the wagons. All three phases of our game are coming together."