Republic of Ireland-qualified Derry-born McClean’s move to the Wearside outfit, a £350,000 transfer from Derry City, went relatively unnoticed during a period of heavy recruitment at the Stadium of Light last summer, and for the first four months of the season he did not make a first-team appearance.
That all changed when O’Neill succeeded Steve Bruce in early December, with the new manager handing McClean his senior debut by bringing him off the bench in his first game in charge.
Since then, the 22-year-old has emerged as a key figure for Sunderland and his winner in Saturday’s 1-0 Barclays Premier League victory at Stoke was his third goal in 11 games so far.
He is certainly making a big impression — not least on fellow Ulster man O’Neill, who was unaware of McClean’s talents before arriving at the club.
“He is performing brilliantly for us,” O’Neill said. “He has had a great, great couple of months.
“Considering everything, I thought he took his goal brilliantly.
“I didn’t know him at all until I arrived at the football club, so to see him blossoming out there has been very pleasing for everyone, obviously myself included.”
The goal came in the 60th minute at a snowy Britannia Stadium, McClean collecting the ball from Stephane Sessegnon, evading Andy Wilkinson and Ryan Shawcross and slotting it past Thomas Sorensen.
The win, earned in extreme conditions with snow falling relentlessly, was Sunderland’s fifth in six league matches and means they have now taken 22 points from a possible 30 under O’Neill.
Having been hovering just above the relegation zone when he took over, the Black Cats are currently eighth in the table, although when asked about the possibility of a push for Europe, O’Neill said: “I think we are a long, long distance away.
“I know I’m like an old gramophone record saying this, but it is the same thing.
“It has been a great, great run and more points than we could have imagined at the start of December. With the way results were, it has been very important for us.
“The players are playing with confidence and good self-belief and that is all you can ask for.”
Stoke, who slipped to 12th, were reduced to 10 men in the 45th minute with defender Robert Huth shown a straight red card by referee Martin Atkinson for a sliding challenge on David Meyler, a decision that left Potters boss Tony Pulis enraged.
Pulis indicated afterwards he was likely to appeal against the sending off and suggested play-acting by Meyler contributed to the German’s dismissal, claiming his reaction was the sort of thing Professional Footballers’ Association chief executive Gordon Taylor needed to speak to players about.
The Welshman did, however, have more general praise for both teams for the way they coped with the conditions.
“We have had two home games this year — one against West Brom where we had a gale force wind which nearly led to the game being called off, and now we have had snow and bad conditions here,” said Pulis, who confirmed that Potters forward Cameron Jerome had come off in the first half due to a dead leg.
“I think credit has to go to both sets of players. They have given it their best, and that is all you can do. I thought it was a very difficult game to play in.”