"He's got a boy that plays in the team we played against. He had a massive impact on the game.
"They were coming in from behind, pushing off the ball, hacking players down."
Travelling the last two hours of trip from Ashurst to Fern Hill in pouring rain conditions, City arrived to find officials had to use buckets and squeegee mops to try and clear out the worst of the puddles at Petane Domain before kickoff.
However, it was not the tough muddy conditions which Francis thought cost his team the game.
"To come from 2-0 down to pull it back and force extra time, we just didn't keep our heads enough.
"Trying the long ball [because] in the middle we would lose it. With sore ankles."
Jake Lockett had a shot on goal midway through the second half of extra time, but the United keeper got a foot to it.
"They kicked a long ball over the top, their guy scored what was to be the winner," said Francis.
The second half fightback was started by a Latham Berry free kick from 40m out which struck home, while Kyle Graham-Luke added a penalty to tie the scores.
Francis said Berry had a strong shift in the middle of the pitch, while Eli Fleming was the team MVP after a very strong game.
United had gone 2-0 up after 45 minutes, with one of their goals coming from a penalty which was called for an earlier infraction after Tom Dixon had made a fair challenge to regain possession.
Francis said the linesmen also pointed out a couple of infractions where City should have received the penalty, only to be over-ruled by the official.
"I've got to be be careful what I say, because I was asked to leave the field too," he said, which came when he queried those calls.
His letter to Central Football will question the appropriateness in future of appointing family members of players to referee important cup fixtures.
"They rang to give us a heads up, 'but we don't think we'll have any problems'. Well, no [we did].
"As Latham [Berry] said, 'nothing we can do about it now'.
"They go to the quarterfinals."
City will have a break from their usual training tonight, then have a run through on Thursday ahead of the start of the second round of the Lotto Federation League, when they meet GJ Gardner Wanganui Athletic in the return derby game.