The gamble paid off for Heimir Hallgrimsson, with Evan Ferguson delivering on his return to the starting eleven as Ireland came from behind to beat Bulgaria 2-1 for the second time in three days.
But they had to do it the hard way, as just like in Plovdiv on Thurdsay night, Bulgaria scored first, forcing Ireland to hit back twice in the second half to seal the win and the overall aggregate victory to retain their UEFA Nations League second-tier status.
It was another bright start to the game from this ever-improving Ireland side, and they had Bulgaria pinned back inside their own half for the opening ten minutes with chances falling to Jake O'Brien, Finn Azaz and Mikey Johnston.
Bulgaria were just about coping before they finally worked their way up the field for a corner, which was essentially their first chance to attack – it had taken half an hour.
But just a couple of seconds were needed to take the unlikely lead, as another hopeful punt from distance reopened old wounds with Ireland again conceding a soft goal to fall behind.
Georgi Milanov’s volley was blocked en route to goal, however, neither Nathan Collins nor O’Brien could clear the loose ball allowing Valentin Antov to seize the initiative.
It took a while, but Ireland did get themselves going and another O’Brien header from a corner caused real trouble, but this time it was cleared off the line.
For all the good Ireland play in the opening 45 minutes, it was Troy Parrott and Azaz who were showing the creative spark while Ferguson was struggling to contribute in attack.
There was a sense that the young striker was on borrowed time as the second half progressed, however, he burst into life in the 55th minute with a well-saved shot from distance.
An in-form centre-forward may have backed himself to take it in closer and slot it home, however, he did hit the target with a positive driving effort and it probably afforded some extra minutes to impress.
And to his credit, he showed his quality, and hunger, by creating something for himself by dropping deep, then working a great one-two with Azaz before whipping the ball into the roof of the net.
That equalising goal putting Ireland back in control of the play-off, however, the plethora of substitutes would come soon after, and Adam Idah then made his point to the manager by delivering the winning goal six minutes from time to seal back-to-back victories with the tie ending up 4-2 on aggregate.
Idah, no doubt, would have felt aggrieved to be overlooked in place of Ferguson in the starting eleven considering his club form has been impressive at Celtic over the past few months, however, there was always a sense that Ferguson was ahead of him in the pecking order.
"An educated risk" was how assistant head coach John O’Shea described the decision to go with Ferguson from the start despite having little club form to justify the decision in recent months.
Ferguson, however, did start the last four games in a row for the manager in October and November and had no doubt built up a bit of credit with Hallgrimsson to trust him from the start.
"That was the balance," said O’Shea, when asked whether Ferguson’s selection was based on more than just club form but previous games and his showing at training.
"When we saw first hand the freshness he had when he came on [in Plovdiv], the problems he caused the Bulgarian centre-backs, we felt that it was an educated risk in that sense to know that he was going to cause them problems.
"We were aware what minute, whether we assess at half-time and after that then see how he reacts in the second half, and you could see that the tank was running empty when we did take him off.
"The most important thing is that we have a healthy Evan Ferguson, a fitter Evan Ferguson each camp that goes by, and hopefully that will be the case.
"West Ham know him, the manager knows him very well, so hopefully they’re getting a much fitter and happier Evan Ferguson in that sense going back with minutes in the tank and a goal as well."
Finn Azaz's creativity was evident throughout the contest
One player who has certainly grabbed his opportunity to impress the manager ahead of the World Cup qualifying campaign is Middlesbrough play-maker Finn Azaz who scored his first international goal on Thursday night in the first leg, while again showing his creative side to inspire Ireland to another victory.
Azaz was forever attempting to push the side forward and was responsible for the most creative aspects of the first half, which went unrewarded.
But the impressive performance continued in the second half and he had a major part to play in both goals, which will have grabbed the attention of the management team when planning for the autumn campaign.
Creative players have been jettisoned by previous Ireland managers in place of either energy or aggression, however, Azaz’s flexibility should also work in his favour in the group with Armenia, Hungary and Portugal, who beat Denmark over two legs to take their place as top seeds in the World Cup qualifying group.
"I would have to say so," said O’Shea, when asked whether he felt that Azaz would have the trust of the manager against tougher opposition.
"I think Finn has shown that he is more than capable to adjust on the side as well where he can connect in with whether two strikers or a ten or a nine.
"Michael Carrick has used him at Middlesbrough all the way across in behind the striker whether that’s on the left side, right side, or in that central position. I think he has definitely showed his most exciting form in that ten role.
"He’s a very special talent, it’s great to see him progress and hopefully he’s going to be an important player for Ireland."