James Collins said there were "home truths" spoken by players and management in the Ireland dressing-room after their 1-0 defeat to Luxembourg.
"As you can imagine, the dressing-room was really low," he said.
"We got the thoughts of the staff and a few of the players had their say as well, but that will all stay in house, as you can imagine, but there were certainly some home truths spoken there and that can only benefit us going forward."
The Luton striker had the best of the chances for the hosts at the Aviva Stadium and held his hand up.
"It's a really disappointing night, we went out there full of confidence and wanting to get the win, and fully believed we would.
"I fully backed myself to score the first one, I should score, so that's on me.
"But players know that's not good enough tonight, we have to dust ourselves down and regroup, we have to stand up as men and try and do better.
"I completely agree with the manager and Seamus (Coleman), it wasn't acceptable and it was embarrassing, we as players have to take it on the chin and try and do better.
"There's no point dwelling on tonight, we've got to accept it, digest it and be men, and move forward. If we win on Tuesday, albeit it's a friendly (against Qatar), it will give us a lift.
"I can totally understand the viewpoint of the fans, it's not good enough, but we will do our best to rectify that."
Collins said that the players remained behind Stephen Kenny, who is still waiting for a first victory in 10 games in charge of the squad.
"100% it's not the manager's fault that performance tonight, it's the players," said the 30-year-old.
"I'd fully back the manager and all the staff and we should look at ourselves as players and try and get better, and I'm sure that will be the case."
Collins added: "Training's been good but tonight it just wasn't to be, we had chances but it has to be better.
"We wanted to score and had chances in the second half to do it, but Luxembourg came here with a game plan and executed it."
Asked if this was the end of Ireland's World Cup hopes with just two games of the campaign played, Collins responded: "Certainly not, and there's no point in any of us thinking like that because it's not going to get us anywhere.
"First of all we have to get ready for Tuesday and get a win that will give us a lift, then regroup.
"I'd never say the World Cup campaign is over because it's not an attitude we should have."
