Only one person had/got a 'perfect score' on the test. [=only one person answered all the questions correctly]
If you're 'keeping score' at home, this is the third time that he has run for mayor and lost.
The 'score' was tied at 1–1 [=each team had scored one run] after the second inning.
(..) Bet you a million bucks UCLA wins it -. - What are you, deaf? It's over. You lost. - Yeah? All right. What's the gag? How did you know what the score would be? OLD BIFF: I told you, it's in this book. All you got to do is bet on the winner, and you'll never lose. All right. I'll take a look at it. (..)1989 Back to the Future Part II