As Franklin pitcher Kara Wingate's wild pitch skipped past catcher Jessie McGraw in the top of the first, Fallston's Lauren Heisey immediately broke from third base and raced toward the plate.
McGraw quickly retrieved the ball and flipped it to Wingate, who blocked the plate and tagged out the sliding Heisey just in time.
The play ended the inning and prevented Fallston from taking the lead. It also was the last time the Cougars would come close to scoring.
Wingate allowed just one other runner past first and went on to pitch a two-hitter, as the No. 15 Indians edged visiting Fallston, 1-0, in a Class 3A North region semifinal.
Franklin (13-3) will meet No. 14 C. M. Wright in the region final tonight at Harford Community College at 7.
"It turned out to be a big play," Franklin coach Rick Wiscott said. "You don't know in the top of the first how big it is, but I know now how big it was."
Indians center fielder Melissa Wenderoth's RBI single in the third proved to be enough support for Wingate.
The Cougars (12-7) had managed just one hit off Wingate before Katie Wirth led off the seventh with a single.
Wirth moved to second on Emily Weibel's sacrifice bunt and took third on Mindi Karczeski's groundout in a close play at third. She would be stranded there, however, as Wingate struck out Candi Kuligowski, who chased a high fastball.
Wingate, who appeared to gain more velocity on her fastball as the game progressed, struck out nine -- including five of the last nine batters -- and did not yield a walk.
"Everything seemed to be there for me today," said Wingate, a junior. "I was trying a rise and it was working. The changeup worked a couple times. I threw the drop a lot. And my fastball was getting faster."
She also helped to quell two Fallston rallies with her defense, first with her execution on the play at the plate in the first inning. In the fifth, Wingate fielded a sacrifice bunt with none out and easily threw out the lead runner at second.
"What makes her such a good pitcher isn't just that she throws so hard, it's her defensive skills," Wiscott said. "She's a good pitcher, but she's a great athlete."
Fallston's Tisha Bright also pitched well, giving up just three hits, no walks and striking out five. The run she allowed was unearned.
Franklin's Cori Kalmanson reached on an error by shortstop Julie Clark to lead off the third. She advanced to second on a wild pitch and to third on a groundout before scoring on Wenderoth's single.