Why is the third game called the 'rubber match'?
Usually a "rubber match" or "rubber game" of a 3 game series is
only played if no one has a chance to sweep the series. If team A
wins game 1 and team B wins game 2, it shows game 3 can go either
way... Sorta like how rubber can bend either way.
Thus, "Rubber game" of the series.
According to Paul Dickson's The New Dickson's Baseball
Dictionary (Harcourt Brace, 1999), a "rubber game" is "The last and
deciding game of a series when the previous games have been split;
e.g., the seventh game of the World Series." This tie-breaking
sense of "rubber" apparently originated in the pulse-pounding
English game of "bowls," or lawn bowling. Despite its name, bowls
has little in common with American bowling, and consists of rolling
wooden balls (called "bowls") across a level green, the object
being to get your ball as close as possible to (but not to hit) a
little white ball at the other end of the green. "Rubber" in its
tie-breaking sense first appeared in the context of bowls around
1599, and was in use by the card-playing crowd (whist, bridge,
etc.) by 1744. A set of three games of bridge is still generally
referred to as a "rubber."
Unfortunately, no one knows where "rubber" in this sense came
from. It appears to be unrelated to the elastic sort of "rubber."
(Incidentally, our modern elastic "rubber" is short for
"India-rubber," from its original source in the East Indies.
"Rubber" previously meant anything used to rub, smooth or clean.)
Brewer's Dictionary of Phrase and Fable ventures that the term may
have referred to two "bowls" rubbing together, a fatal error in the
game of bowls. Or it might be a metaphorical use of "rubber"
(something that expunges) referring to the "sudden death" third
game of a series, the loss of which would conclusively "rub out"
the losing team's hopes. But there is, sad to say, no solid
evidence for either theory."
I think that 'rubber match' will mean the match that will decide
the rubber ie the fifth in a series of five. The term rubber
doesn't itself mean decisive.