There was plenty of activity on social media within minutes of Giovanni Trapattoni's announcement being made with joy for McClean and sadness for James McCarthy
The Derry man's Sunderland team-mate David Meyler promptly issued his congratulations via Twitter after the squad was confirmed: “Congrats to @JMcC_23 absolutely delighted for you pal, fully deserved you ugly man! #ComeonYouBoysInGreen”
McClean's fellow Derry man and Everton defender Shane Duffy, who missed out on a place in the squad, also sent his well wishes, urging the winger to “do the country proud" at this summer's finals.
Meanwhile, there was an admirable fleet of League of Ireland exiles in the squad, with Keith Fahey, Seamus Coleman, David Forde, James McClean, Stephen Ward, Shane Long and Kevin Doyle included.
Airtricity club Derry City FC were quick to get in on the act and tweeted: "Two ex-Derry City players and a Derry man in the squad. Welcome done to Fordey, James and Darron!"
In Dublin the St Patrick's Athletic Twitter crew punched out: "Best wishes to former Saints Keith Fahey and Kevin Doyle who have been selected for the Republic of Ireland squad for Euro 2012!"
However, in light of the serious news regarding James McCarthy there was a sympathetic reaction from fans, players and colleagues alike.
Giovanni Trapattoni emotionally revealed that McCarthy was in his plans but that he completely understood and respected the Wigan youngster's decision to pull out of the squad and help his father as he battles cancer.
Accrington Stanley striker Padraig Amond tweeted: “Just seen why James McCarthy pulled out. Hopefully his dad gets better! #moreimportantthingsinlife”, while senior defender Sean St. Ledger echoed the sentiment.
The reaction overall was a mixture of happiness and concern; joy at James McClean's eventual inclusion and a swelling of concern for the well being of James McCarthy and his family.