The Wildcats sophomore was four outs from the complete-game shutout until Catoctin got consecutive hits by Jamie LeGore, Sam Geisinger and Jenna Davis to knot the game at 1-1 in the sixth.
A scoreless seventh sent the game to extra innings, with Beard and Catoctin starter Casey Hertel still going strong.
Williamsport took a lead in each of the eighth, ninth, 10th and 11th innings. Catoctin - the defending state champion - answered three times, but came up short in the fourth attempt.
"Not only are they state champions, they always have a good team," Dzur said. "They played like champions today."
Beard singled with two outs to drive in Ali Zube in the top of the eighth to give Williamsport a 2-1 edge. The Cougars were one out from elimination after a double play in the eighth, but Beard gave up a run-scoring double to LeGore to score Lauren Wildasin, who walked, to tie the game at 2-2.
Beard said, "I had it," as the Wildcats prepared to bat in the ninth.
"Of course, it's frustrating," Beard said. "But you just have to come back at them."
The Wildcats regained the lead in the ninth when Wildasin fielded a ground ball at shortstop and fired home to beat lead runner Jess Patey. But Patey slid under the tag and Siler, who singled, later scored on a bases-loaded walk to give Williamsport a 4-2 advantage.
Beard gave up a run-scoring double to Davis in the bottom of the ninth to cut the score to 4-3. Once again facing the final out, Catoctin hit a grounder that was thrown away by Williamsport for a two-base error to knot the game at 4-4.
"I thought we had it a couple of times, but (Catoctin) kept coming back," Dzur said. "To their credit, they never quit."
Williamsport took the lead again in the 10th. Beard hit a run-scoring triple - her second extra-inning hit and RBI - and later scored on an error to put the Wildcats ahead, 6-4.
Three more Williamsport errors helped the Cougars tie the game for the fourth time, 6-6, spelling the end for Beard, who scattered seven hits and struck out six in 9 1/3 innings.
"Kelly threw the ball well," Dzur said. "When they were getting hits off her, they weren't hitting it all that hard. But they were going to the right spots."
Hertel remained in the game and gave up what turned out to be the game-winning RBI single to Emily Myers in the 11th.
Jess Bennett, who relieved Beard in the 10th, had runners on second and third in the bottom of the 11th before getting two strikeouts to end the game.
"I just focused on getting the batters out. I wasn't worried about the runners at all," Bennett said. "Kelly was pitching such an amazing game. I was hoping I wouldn't have to come in. I was a little nervous."