With Dundalk and St Pat’s also winning, it was crucial for City to pick up all three points last night and after an unconvincing performance, O’Sullivan’s second-half moment of magic was the difference in the end.
City manager John Caulfield was forced into making one change to the side that defeated Bray Wanderers last week at the Carlisle Grounds with Brian Lenihan replacing the suspended Billy Dennehy, who was sent off in Bray.
Athlone boss Keith Long made two changes to the side that picked up their first league win of the season against UCD last week, with Philip Gorman and Declan Brennan coming in for Sean Byrne and Derek Prendergast.
Athlone started brightly and looked the livelier of the two sides without troubling Mark McNulty in the City goal.
The home side looked flat in the opening exchanges and missed the creativity and goal threat of the suspended Dennehy. O’Sullivan was isolated in his lone striker’s role and it took until the 29th minute for the first effort on goal when the visitors’ Graham Rusk had a long-range effort easily gathered by McNulty.
The home side, who defeated Athlone 3-0 when the sides met back in March, went close six minutes before the break when Dan Murray’s low ball into the box almost ended up in the net but the ball went out off the butt of Paul Skinner’s right-hand post.
Gary Buckley was inches away from giving City the lead just before the break when he got on the end of John Dunleavy’s long cross but the midfielder’s header came crashing back off the crossbar.
Most in the crowd of 2,875 were expecting a much better second-half performance from the home side and Caulfield introduced the busy Rob Lehane for Liam Kearney at half-time, as the manager went with two up front, in a bid to wake his side from their slumber.
Lehane’s introduction did the trick as City upped the tempo and the youngster went close with a long-range effort early in the second half, before Gearoid Morrissey wasn’t far away with another shot from distance.
The opener did arrive in the 58th minute and it was well worth the wait, as Brian Lenihan picked out O’Sullivan with a super long cross.
The striker still had it all to do however, but spotting Skinner off his line, O’Sullivan planted a superb looping header from 15 yards over the keeper and inside the post for a goal worthy of winning any game.
It was all City now and Skinner had to get down well to deny Morrissey soon after, before Lehane’s flick was hacked off the line.
Substitute Ian Sweeney did go close on the 69th minute for the visitors in one of their infrequent attacks but McNulty made a great stop to push the ball around his post.
Athlone’s slim chances of forcing an equaliser looked to have disappeared when captain Alan Byrne was dismissed for a second bookable offence, when he pulled down Lehane eight minutes from time.
However, the away side almost forced an equaliser in the last minute but Sean Brennan’s backheeled flick was brilliantly saved by McNulty as City held on.
CORK CITY: McNulty; Dunleavy, Murray, D Dennehy, Davoren (Kavanagh 90); Lenihan, G Morrissey, Healy (O’Leary 73), Buckley, Kearney (Lehane 45); O’Sullivan.
ATHLONE TOWN: Skinner; Quigley, Byrne, D Brennan, Clancy; S Brennan, Dillon, Hughes, Marks (Sweeney 64); Rusk (Harney 87), Gorman.
Referee: P Tuite (Dublin).