Kyle Crist singled to right to bring up Thurber, who drilled a liner to center which appeared catchable by Adams, who misjudged it as Kehr came streaking home.
"(Adams) took two steps in, misjudged it and couldn't get back," said South coach Ralph Stottlemyer.
Clear Spring (8-2), which had only three hits through six innings off Shank, got a one-out double by Matt Braithwaite. After a popout, Brandon Glazer hit an infield single with Braithwaite going to third. Kehr then roped a single to center to score Braithwaite and forge a 3-3 tie -- Clear Spring's only earned run of the game.
"We scored two cheap runs early and went into cruise control," said Shives. "Right now we're doing just enough to win and I don't subscribe to that theory around here."
Clear Spring's runs in the first and third were unearned. An error by Tim Hoover in the first and a throwing error by Shank that wiped out a potential double play in the third hindered the Rebels.
South (3-7) touched Kehr for a pair of runs in the third to take a 2-1 lead. Hoover singled and scored on Joey Miller's second homer of the year, a long shot to right-center.
Those were two of only four hits Kehr allowed through six innings before yielding to Glazer, who picked up the win with three innings of one-hit ball.
The Rebels had a two-out uprising of their own in the top of the sixth to grab a 3-2 lead. Adams walked and scored on a double by Trevor Haupt that landed at the base of the fence in deep center.
Kehr, playing second base after departing the mound, made a defensive gem in the top of the eighth.
Tyeler Presgraves led off with a single. Kehr snared a one-hop smash by Miller and turned it into a double play.
"An easy grounder, a blooper ... you've gotta make those plays," said Stottelmyer. "It's frustrating for the kids and I know they are now. I've got to get them back up. This game should have been over in seven innings."
Shank threw only 86 pitches through seven innings before going to extra innings.
"(Cory) pitched a great game ... said he was strong coming out in the seventh and he said he was strong in the ninth," said Stottelmyer.
Shives was equally impressed with Kehr's six-inning stint, which included five strikeouts and only one walk.
"(Josh) threw well, what more could we ask for," said Shives. "It was his best day and he made a big play defensively."
Clear Spring 4, South Hagerstown 3
South 002 001 000 -- 3 5 3
Clear Spring 101 000 101 -- 4 10 1
Shank and Haupt. Kehr, Glazer (7) and Morgan. Wp -- Glazer. LP -- Shank (1-2). HR -- SH: Je. Miller (4th, one on).