Already without the suspended Robbie Brady for Friday night’s Group D clash at the Aviva Stadium, O’Neill on Monday saw playmaker Wes Hoolahan added to a casualty list which includes central defenders Shane Duffy and Ciaran Clark, and midfielder Harry Arter.
Everton’s James McCarthy and Newcastle’s Daryl Murphy could miss out too with Ireland rapidly running out of options, although their manager is confident he will still be able to field a competitive team.
Asked for an injury update, a frustrated O’Neill said: “How long have you got? It’s the lengthiest list of injuries that I have known since I have come into the job, and unfortunately it’s happened at a really crucial time for us.
“However, other players will have to step up and just be ready for Friday. Do you know, I have often said this before, that you just curse your luck and get on with it.
“The irony of all of this here is that way back when Gareth Bale got injured in November-time, everybody was talking about Wales possibly having one of their major players out of the team, and it turns out that we are the ones who are doing the suffering.
“But it is what it is and we’ll get on with it and we’ll be ready to go on Friday.”
Striker Jonathan Walters has been around the Republic squad long enough to know they are often at their best when their backs are against the wall, and is hoping the same applies this week.
Walters said: “Over the course of the past few years, we’ve been underdogs in a lot of games and got the result we wanted.
“We showed that in the summer [at Euro 2016], such a difficult group to get out of and we did, and we’ve shown that in this campaign so far.
“It’s another difficult group to get out of, but four games in we’re sitting pretty at the moment.”