The Mermaids, which had a perfect regular season, have six days to re-focus before game two, after going down 64-59 to a physical Warrandyte outfit yesterday.

Still reeling from the "painful" defeat, coach Peter Davis said the team must regroup before this weekend's Big V division one double-header in order to secure a grand final spot.

"We lost our composure from the point-of-view of controlling the game," he said.

"The girls had it under control most of the game but we just really lost our way a little bit in the third quarter.

"We should've had it."

Davis said he was "very surprised" Warrandyte was awarded 47 foul shots while his side had 25.

"I haven't had calls like that ever before," he said.

"The girls tried to adapt but they couldn't maintain their intensity.

"(Warrandyte) ended up scoring 31 points from the foul line out of their 64 points and that's interesting to say the least."

Davis said the Mermaids would focus on their intensity at training this week before hosting Warrandyte in cut-throat matches at Warrnambool's Arc stadium.

"The fact of the matter is we have to win the next two games to progress so we just have to go back and keep at it," he said.

"Hopefully the loss is something we can come back twice as strong from."

The Mermaids yesterday gained an early lead on the home side, up 22-11 after the first term.

Strong defensive pressure saw the Mermaids retain their lead in the second quarter to finish 10-points up.

But the Venom suffocated the travelling side's scoring opportunities, scoring 20-8 in the third term, setting up a two-point lead at three-quarter time.

The Mermaids struggled to stop the Venom's scoring opportunities and went down by five points.

Mermaids top scorer Katie O'Keefe finished with 12 points, four assists, three steals from her 38 minutes on court.