That brought out manager Junji Hidaka's inner Yogi Berra and sparked a record rally that saw the Kitasuna Little League pound out 22 hits in an 18-11 comeback victory in a battle of undefeated teams.
"I told the players it doesn't end until it ends," Hidaka said through a translator.
Japan responded with seven runs in the second, four in the third inning and five in the sixth.
Masafuji Nishijima had four hits and six RBIs, and Shingo Tomita hit two of Japan's five home runs.
Japan's third pitcher, Nobuyuki Kawashima, held Lewisberry in check most of the game, giving up just one run and two hits over five innings.
"Today my fastball wasn't going fast enough," said Kawashima, a 12-year-old who lived for four years in California and speaks fluent English. "I knew my breaking ball had to be on the corner, down low, where the batters can't reach too far or it just gets them off-balance."
It was the 10th title for Japan, second behind Taiwan's record 17, and Japan has won four titles in the last six years, becoming the first international country to do so since Taiwan won five spanning 1986 to 1991. It's the third title for the Kitasuna Little League team, which also took home championship pennants in 2001 and 2012.
Japan had given up a total of 10 runs in its other tournament games, but Pennsylvania scored 10 times and sent 14 batters to the plate in the bottom of the first after falling behind 2-0.
Pennsylvania knocked out starting pitcher Daiki Fukuyama before an out was recorded in the first. Dylan Rodenhaber made his first hit of the tournament count, hitting the ball over the right-field fence for a grand slam. Jaden Henline added a three-run homer, a shot that went deep into the shrubbery in straightaway center field.
The Red Land Little League, which draws players from several central Pennsylvania towns around Lewisberry, scored three more times, sending what amounted to a hometown crowd of more than 42,000 fans into a frenzy.
Fans of the Lewisberry team helped set a tournament attendance record of 499,964, well over the previous mark of 414,905 set in 2011, when a team from Keystone, Pennsylvania, was in the tournament.
Japan responded after its manager's pep talk. Yugo Aoki hit a three-run homer in the top of the second, which was followed with solo shots from twin brothers Kengo and Shingo Tomita.
Fukuyama added a two-run double up the middle to bring the Japanese back within a run.
Shingo Tomita tied the score at 10-10 in the third inning with a solo home run to left field. Three batters later, Masafuji Nishijima hit a three-run homer to make it 13-10.
"They just put the bat on the ball," Pennsylvania manager Tom Peifer said. "They hit pitches I've never seen kids, especially 12-year-olds, hit."
Pennsylvania got one back in the bottom of the third. Braden Kolmansberger hit the ball over the head of Japan's center fielder and eventually scored when third baseman Koki Jo could not handle a slow roller by Henline.
The teams broke the previous Little League record of 23 combined runs in a championship game -- a mark that had stood since 1947. Pennsylvania's 10-run first inning also was a record, as was the teams' combined 30 hits. The eight-run deficit was the largest overcome in any Little League World Series game.
Japan had not won a game by more than two runs all tournament and had won its past two in the team's final at-bat.
It used the final inning in the championship game to add five insurance runs, highlighted by Kengo Tomita's triple that scored Aoki and opened the floodgates.
Pennsylvania came in with four World Series titles, but the last was in 1960, when a team from Levittown accomplished that feat. Lewisberry is the first in-state team to win the U.S. title since a team from Shippensburg did it in 1990.
"There are a lot of tears, even from myself, to know that the run is over" Peifer said. "But we quickly told them, 'When we leave here, let's get the tears out, because there is nothing to be sad about.'"
U.S. teams are now 15-35 all-time against international teams in the final.
In the third-place game played earlier Sunday, Texas defeated Mexico 6-4.
The Associated Press and ESPN Stats & Information contributed to this report.
Japan beats Pennsylvania in record-setting LLWS title game
Japan outscores the U.S. team 16-1 after the first inning, with the teams combining for a LLWS title-game-record 29 runs, as Japan wins 18-11.
Japan wins Little League World Series
Japan shortstop Yugo Aoki throws to first to get the final out of the Little League World series against Pennsylvania.
LLWS: Japan ties game, climbs back from 10-2 deficit
Shingo Tomita slugs a home run to left field, allowing Japan to rally from a 10-2 deficit and tie Pennsylvania at 10 in the top of the third.