A 1-0 loss to the United Arab Emirates has put enormous pressure on the Olyroos to beat Vietnam in their next match of the AFC U-23 Championship in Doha (Kick-off 12.30am Monday AEDT time).
In terms of being one of the two teams to advance from the group, a draw would leave the Aussies facing a must-win game against Jordan and possible still needing the other result in Group D to go their way - while a loss to Vietnam would most likely be catastrophic.
Gersbach told The World Game he and the rest of the players knew it was now or never.
"There's a lot of pressure on us now," he said. "We have to aim at nothing less than a win against Vietnam.
"We've got to aim at getting two wins from our remaining two games and that should be enough to make sure we get through.
"'Viddy' (coach Aurelio Vidmar) told us it wasn't going to be easy. We all knew it was going to be tough and that there may be setbacks.
"We could drop a goal here, we could maybe lose a match or draw one, you know what I mean, so we were prepared for that possibility and having to come back from it.
"Now we've just got to stay focused and really relish the challenge and fight for our country and try to get as many points as we can in these next two games.
"We believe we've got the ability and the character to do that. It's the Aussie spirit, I guess, and we really need that now."
Gersbach said there wasn't much said in the dressing-room after the loss to UAE and that the full debrief came at a team meeting the next day. He said it was critically important the players stay upbeat and positive about their chances going into game two.
"The loss was a bit of a wake-up call," Gersbach said. "We were really confident coming into the game and to be beaten that way (by an own goal in the 85th minute) was very disappointing, but we've got two games left in the group stage and we've got to forget about that result.
"The good thing is we've got another game coming up quickly and we've just got to focus on that and make sure we get the three points there and then try to do the same in the third game.
"Everyone was really dejected in the dressing room after the game. Not much was said. Everyone was just reflecting on the game and was pretty upset.
"Viddy just said it wasn't good enough, which is right, and that individually and as a team we've got to be better and that we have to pick up our game from here.
"So now we move on and everyone has got to wake up with a smile on their face and be happy and positive and we've got to win our next game, that's just how it is.
"We can't be moping around the hotel with our heads down, we've just got to get ourselves up and enjoy what's going on and look for a more positive performance in the next game. Hopefully create more chances and score a few goals.
"We won't dwell on the result in the first game. There's nothing we can do about it now. We've just got to focus on the next game and prepare for that."
Connor feels the pain of a missed opening
Gersbach said the Olyroos knew UAE would sit back against them and look to counter-attack but that despite the proactive approach of the Aussies they just couldn't find a clear way through.
"We dominated possession, but we couldn't create enough chances," he said. "They were pretty compact and they were feeding back, so while we had a lot of possession it was mostly in the defence and in the midfield.
"We couldn't seem to find those penetrating passes going forward. We found it hard to get in behind them and when we did get in behind them we still found it hard to provide for our strikers.
"They played as we expected them to and I thought our defence did well for most of the game to keep them out.
"They didn't really trouble us for most of the game but as it wore on bodies got tired and we got a bit sloppy at the back and made a few mistakes which led to a few chances for them."
