Continuity mistake: In the championship game - last at-bat, Kelly hits the ball to right field. They show the outfielders throwing the ball in from the fence with the scoreboard showing Yankees scoring 3 in the 6th inning and a total of 6, with no run total for the Bears. The camera angle switches to Kelly rounding third and then back to the outfield again. Now the scoreboard shows Yankees total 7 runs and Bears 3.
Continuity mistake: Adding to Kelly Leak's homerun in his first at bat shown in the movie (great scene with the ball hit during practice and clears the fence during a game), the celebration at home plate does appear to indicate a game winning homerun (a walk-off no less). However, as the ball clears the fence you can see the score is 0-0 in the top of the third. (00:57:52)
Suggested correction: It was probably just excitement that someone on the team finally hit a home run. This was a bumbling team (remember their first game they didn't get a chance to even bat) and were lacking hits and runs until now. Most likely a confidence booster for the team.