I've come across the phrase "daylight coming in second" several times of late and am not 100% sure of the meaning. Here are several (1,2,3) examples where it appears which leads me to believe it may be an Australian idiom, something akin to "a clear winner". Does anyone know the meaning and origin of this phrase?
It certainly does mean that someone or something is a clear winner, with the gap to the next place getter being so large that all you can see is daylight. It is a common enough Australian expression, and if it did not originate in the horse racing circles, it is most definitely one of the most commonly used expressions to describe when the first horse over the line wins by a very clear margin. It is described in this glossary of Australian punting terms