Northern Ireland boss Michael O'Neill maintains his players still believe they can reach Russia and will not dwell on the penalty decision that could scupper their World Cup dream.
It is Switzerland who are currently on course to emerge from the playoffs with a finals ticket, having won 1-0 in Belfast thanks to a dubious penalty that still stings Northern Irish fans.
O'Neill insists his players are concentrating on overturning the deficit in Basel on Sunday, rather than stewing over referee Ovidiu Hategan believing Corry Evans handled Xherdan Shaqiri's shot.
"There's a lot of emotion in the dressing room after the game which is natural -- but it's gone now," O'Neill said. "What happened in the game, we have to take motivation from it, but it's gone now in terms of where it is in the players' mind and the focus is on trying to get the result that could take us through.
"I said to the players on Friday what's happened has gone, we've got to leave it behind, it's not something we need to dwell on. Our focus is on what lies ahead, and not the officials."
Switzerland's Granit Xhaka similarly wants the moaning about the penalty call to stop, as he is confident his side are superior regardless of the decision.
"I don't know why it is such a big topic or why there is such a big discussion around it; we should leave it," the Arsenal midfielder said. "We were the better team and we want to show it again on Sunday and qualify for Russia. We are a good team.
"We are maybe the better team compared to Northern Ireland and on Sunday, with all the support that we will have behind us, we want to make them proud and qualify for the World Cup.
"To discuss the penalty, and whether it was a penalty or not, it is the decision of the referee and not of interest to us.
"It is difficult to play Northern Ireland -- defensively they are very strong -- but I thought we played a good match from the beginning in Belfast and created a couple of good chances.
"Sunday is a totally different game. Both teams will act differently but I think our victory in Belfast was deserved."
O'Neill was also incensed that referee Hategan only gave a yellow card to defender Fabian Schar for a wild fifth-minute hack at Stuart Dallas that injured the Leeds winger and looks to have ruled him out of Sunday's game.
Yet Swiss boss Vladimir Petkovic argued the Romanian official was "good in general." He instead focused on Hategan missing what he thought was a shirt-pull on Stephan Lichtsteiner in the box when he gave Northern Ireland a free kick instead.
Asked whether he would be so accepting of the penalty decision were the boot on the other foot, Petkovic replied: "I would accept it, of course -- as a professional sportsperson I would accept every decision made by the referee.
"Of course it has been talked about a lot but there were other decisions, in the 85th minute for example, and these decisions went against us. It is always difficult but I would always accept the decisions of the referee.
"I've analysed the match again and there were decisions that went against us, especially in the 85th minute. I thought the referee was good in general and I thought we won deservedly."
For Northern Ireland, overcoming their position to qualify will be a tall order given Switzerland have won nine competitive games on the spin at home and England are the only team to have won a qualifier on Swiss soil since 2008.
No European team has ever advanced through the play-offs after losing the home leg first too and the Northern Irish have now suffered three defeats in a row -- to Germany, Norway and Switzerland, scoring just once in that time.
However, O'Neill insists his players are not mentally shot.
"I don't think they're short on confidence, I don't think they're short on belief," he added. "It's different from qualification because Switzerland have been to the last 16 of the last two major tournaments. It lifts the level from qualification and we have to get to that level. That's the challenge.
"There's still a lot of confidence and belief in the group that they're capable of coming here and making things difficult for Switzerland, and hopefully we get the result that we are after."
O'Neill offered no update on the fitness of Stuart Dallas, who picked up a foot injury on Thursday, but it was telling that he took no part in the training session open to the media on Saturday.