Blues coach Matt O'Brien said predicted rain could make it a grind against Port Fairy in Sunday's first semi-final at Leura Oval.

"We don't mind it heavy, we don't mind it a little bit slower either," he said.

"We have a lot of people who can win their own footy and can move it forward so a really wet day won't hinder us.

"They would be similar, they have some good heavy, in-and-under players also."

Port Fairy advanced to the second week of finals after a come-from-behind win in the wet against South Warrnambool in the elimination final.

The Blues' qualifying final defeat to Koroit was in dry conditions.

Warrnambool defeated Port Fairy in their two home-and-away matches in 2019, fuelling the Blues' belief.

"It gives you a lot of confidence," O'Brien said.

"The first time we played them they were undermanned and the second time we played them over there (at Gardens Oval) it was a really good match.

"It was a strong arm-wrestle for four quarters and we just got away with the points."

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