Austria have since equalised, however - Allen's Stoke team-mate Marko Arnautovic putting the home side on level terms as they approach half time in Vienna.
It's a hard place to come if you look at their record in qualifying.
"During the Euros they were lucky that a match did not turn in another direction", he said.
"There are still many hard games ahead in this group and we need to be courageous in Serbia on Sunday".
They drew one and lost two of their three group games to finish bottom of the section and suffer a swift exit from the tournament.
And it's now surely certain they've been having us all on, with the Vienna team pic seeing just four players lining up in the back row and the seven others spread out in a bizarrely lengthy front row.
The result is unlikely to change Coleman's desire to never see the kit again, particularly with Allen also handing him an injury headache after being forced off. "He's Stoke's player and we respect that". "I don't think Wales is only Bale". No team is unbeatable, but for us to come here and not bring our A game and get a point says a lot about this team. "We grinded out a two-all".
This was only Wales' second win in five games under manager Chris Coleman as Gareth Bale scored the opener and sent in the cross that gave Sam Vokes the chance to head the victor.
And Sunderland representative, Robert Cooke, is set to take in tonight's match, along with scouts from across Europe, including Norman Wooster, from Newcastle United. The tournament has obviously given us confidence and shown we can stand up against the best teams. It was a very good atmosphere.
Wales then rode their luck before regaining the lead in first-half stoppage time. Austrians really ramping up the pre-game atmosphere.
"You've got to have those expectations to push yourself as far as you can go". The fighting spirit was fantastic. "We were making trouble for ourselves and that's not like us". That's not like us.