Wearside was buzzing on Saturday evening, hours after the Black Cats' 4-2 home defeat by West Brom, as rumours of the Ulsterman's departure spread like wildfire with the help of Twitter.
But O'Neill, who will celebrate 12 months at the Stadium of Light next month, admitted: "Yes, it was a bit of a surprise, really. There was nothing in it. Anybody can tweet these days. I think it happened a couple of years ago as well, something like that, a similar sort of thing. But that's the nature of it. But no, I was pretty surprised."
It was not the first time talk of O'Neill's impending demise had swept the city in recent weeks, but as he prepared his players for Tuesday night's Barclays Premier League clash with QPR, the manager was adamant that it was business as usual.
The speculation has come amid a sequence of poor results for Sunderland, where less than a year ago fans had hailed the arrival of O'Neill as their long-coveted manager. A run of seven wins and a draw in his first 10 league games enhanced his reputation with fans delighted at his arrival.
However, the last 26 league games have brought just four victories - the last three of them against sides reduced to 10 men - and yielded only 24 points from a possible 78.
O'Neill said: "We have got a fairly lengthy time to go. It's an important game, it's every bit as important as the game against West Bromwich Albion, and the one against Fulham, of course. It would be nice to win the match. I wouldn't say it's going to define everything, but all games are important."
The Black Cats' hopes of securing a morale-boosting victory are not being helped by injuries to defender John O'Shea and midfielder Lee Cattermole, both of whom are fighting against the clock to recover.
In addition, they will be the first side to encounter Rangers under the leadership of new manager Harry Redknapp, and O'Neill is well aware of the galvanising effect the former Tottenham manager's arrival could have on an expensively-assembled squad.
He said: "We are not capable of treating anybody lightly, far from it. We are not good enough to do that at all. But in many aspects with him coming in, it's a game for us that we know now the players' concentration has to be absolutely at its height."
Source: PA
Source: PA