"In the second half, we were just going to come out and play like we'd played in the first, but with 10 men, it makes it hard to do that."
The card came when AFC broke away from City, the ball was at the foot of Zane Robinson who was zoning in on goal with City defender Sinton Thomas nearby and goalkeeper Glenn Graham to beat.
Thomas caught up, slid in and clipped Robinson's legs just centimetres shy of the penalty box, denying him a shot at goal.
The tackle was deemed illegal and referee Phil Walker flashed his red card at a red-faced Thomas to end his game.
AFC's Nathan Cooksley took the free kick, he was brilliant and banged the ball into the back of the net.
Earlier, City opened the scoring through a header from Jordan Joblin-Hall, who latched on to a precise cross from Anthony Bell.
Robinson was crucial for AFC and he replied with a headed goal of his own from a corner kick that he earned.
At 1-1, City took over and it started with Joblin-Hall again.
He executed a cross field pass to teammate Max Davidson, who cut the defence to shreds and kicked through for Kyle Graham-Luke who put it home one-on-one with AFC goalkeeper Rowan Holland.
Now 2-1, momentum was with City at halftime.
"I thought we played very well in the first half, we put them under pressure and we did all the things we talked about doing during the week," Francis said.
"We probably had a couple more chances we could have taken, but they defended well, we lacked a little bit of execution there in the first half and then the second half just got away from us."
Thomas's red card and the resulting free kick goal from Cooksley halted City's momentum. Suddenly passes were not sticking, tackles were sluggish and City were frustrated.
No more so than when AFC took the lead after substitute Jona Mufunda headed in another corner effort.
Up by one, AFC looked to shut up shop, but City were desperate and it was evident in their play.
City's Joshua Jonas flew in with a late tackle on Cooksley, who got up and shoved Jonas - the two exchanged words and Jonas was shown a yellow card.
This fired City up and soon enough Joblin-Hall was at it again, drilling an absolute screamer into the back of the net from distance to level the scores at 3-3.
But they could not hold on.
AFC's super sub Mufunda performed some crazy acrobatics, just connecting with an overhead kick from a deflection which sent the ball slowly towards the goal.
The direction and slow pace at which the ball travelled caught goalkeeper Graham off guard, he went the wrong way, lost his footing and could only watch the ball dribble over the line.
"It's a bit gutting really, I thought we deserved at least a point out of the fixture, we battled hard enough, but ill-discipline at the end of the game cost us," Francis said.
"Set play and defending are definitely a focus for next week. Our attack's fine, we spread the ball well, we played some fantastic football here today, but at the end of the day, we get nothing for it."