Egan’s first-half header had taken Ireland to within a minute of arguably the biggest victory in their history at the Estadio Algarve on Wednesday evening when Ronaldo, who had earlier seen his penalty saved by Gavin Bazunu, levelled and then won the game deep into stoppage time.
Defeat in Faro means Stephen Kenny’s men are still to collect a single point three games into the campaign, but amid the bitter disappointment was a recognition that they have something to build upon ahead of Saturday’s clash with Azerbaijan and Serbia’s visit to Dublin three days later.
Egan said: “We’ve got another game. It’s a quick turn-around and we have to dust ourselves off quickly and we have to build on this.
“We had a really good camp in the summer, a couple of really good performances and we’ve backed that up with a really good performance here.
“We didn’t get the result, which is obviously gutting with how the game went, but we can keep building, we can keep improving and I’m sure there is a lot more to come from us.”
Ronaldo equalised with an 89th-minute header and then repeated the dose six minutes into added time to snatch the points.
Former Under-21s boss Kenny has overhauled the squad he inherited from Mick McCarthy, and there were encouraging displays from players both old and new in Faro.
Egan and Shane Duffy at the back limited Ronaldo well for much of the contest and Norwich youngster Andrew Omobamidele did not look out of place when thrust in at the deep end in the wake of Dara O’Shea’s injury.
Josh Cullen and Jamie McGrath prospered in midfielder, while front two Aaron Connolly and Adam Idah increasingly caused problems as Ireland hit their hosts on the counter.
Egan said: “We were really, really good in the first half and we caused them a lot of problems on the counter and defended really well. Obviously as the game goes on, you are kind of hanging on a bit, but we still felt comfortable.
“We played really well, it’s really hard to take, but we just have to take the positives from it. We came away to a world-class team who were European champions not so long ago, who have some world-class players, and put in a really good performance. There are a lot of positives to take.”
For Egan, there was also the personal landmark of a first senior international goal, an achievement witnessed by his mother Mary, his sister Maureen and his fiancee Laura among the crowd.
The Sheffield United defender said: “They managed to get in, my mum, sister and fiancee. It was funny, really, I saw my mum as soon as I scored. It was a special moment.”