Una idea.
Buena suerte y saludos del Oso ¶:^)

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Note added at 2005-05-03 19:20:42 (GMT)
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too close to call
Resulting in too narrow a margin to make a decision, as in That ball didn\'t miss by much but it was too close to call, or The election was too close to call, so they decided to have a runoff. This expression comes from sports, where call has signified “a judgment” since the mid-1600s. In the 1960s it began to be applied to pre-election polls and then to the outcome of elections.

The American Heritage® Dictionary of Idioms

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Note added at 2005-05-03 19:23:33 (GMT)
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reñido
2. adj. Dicho de una oposición, de una elección, de un concurso, etc.: Que presentan mucha rivalidad entre los oponentes.
DRAE©