Radnor went 0-5 to begin the season, played the first 11 games without speedy centerfielder Connor Wilson because of a rare illness, and lost two of its three pitchers to injuries.
The Raiders remarkably overcame those obstacles to claim the PIAA District 1 Class 3A baseball championship.
Mark Jordan's fifth-seeded squad did all of its scoring in the top of the first inning and blanked second-seeded Upper Moreland, 3-0, in the final Wednesday afternoon at Glen Mills.
"These players really know their roles and they buy into what we're trying to accomplish as a team," Jordan said.
Radnor junior lefthander Will Hoysgaard walked seven but struck out five and allowed only three hits in six innings. The Golden Bears left 10 baserunners stranded.
"With guys on base, [Hoysgaard] toughened up," Jordan said. "He buckled down, got some groundouts, and several times got out of trouble."
The Raiders (13-10) will take on District 3's fourth-place qualifier, Cedar Cliff (14-9) or Cumberland Valley (15-7), in the first round of the state playoffs Monday at a neutral site and time to be determined.
"It's pretty amazing that we're in this position," Wilson said. "No one really expected it after the start we had this year."
Last fall Wilson was found to have myocarditis, a disease marked by inflammation and damage to the heart muscle, and spent 12 days at Children's Hospital of Philadelphia.
"I experienced chest pain on the plane ride back from a baseball showcase in Arizona," the 18-year-old said. "It was random and confusing. Once I was in the hospital, I had to embrace it."
Doctors told Wilson, a Dayton recruit, not to participate in any sport for about seven months. The 5-foot-10, 175-pound senior's first game for Radnor was April 27. "He just kept battling to come back," Jordan said.
The Raiders' three-run first was aided by two errors and a walk. Wilson reached first base on a misplayed grounder, stole second, and scored on Matt Schaefer's single to right field.
Upper Moreland (17-4) drew a pair of one-out walks in the sixth. But Hoysgaard (5-5) ended the threat by inducing a double-play grounder to third baseman Pat McDermott.
Radnor 300 000 0 - 3 4 1
Upper Moreland 000 000 0 - 0 3 3
WP: Will Hoysgaard. LP: Joe Bates.