The Scot opened the scoring late in the first period, after Stephane Sessegnon's sliced effort fell right at his feet, and Saints failed to mount any real pressure after the break
Sunderland ended a dismal run of away form to record a vital 1-0 win away against Southampton on Saturday, giving themselves some breathing space from the Premier League relegation zone.
In what was a crucial game at the lower end of the table both teams took a while to get going, aside from a splendid early effort from Stephane Sessegnon. The visitors took the lead through a fortunate Steven Fletcher goal just before the break, and held on after it to secure three huge points.
Nigel Adkins made two changes from the win over Reading, with Gaston Ramirez and Emmanuel Mayuka replacing the injured Adam Lallana and dropped Jay Rodriguez. Martin O'Neill made just the one change, Titus Bramble making way for Danny Rose with Steven Fletcher fit to start.
Sunderland came out of the traps the quickest, with Sessegnon nearly opening the scoring with just seconds gone in the game, but his powerful long-range effort was tipped expertly wide by Kelvin Davis.
The action was a lot less frequent thereafter, though. Jason Puncheon wasted a decent Saints opening by missing the ball completely when in a good position, before Rickie Lambert's free kick was deflected just wide. Meanwhile, Sebastian Larsson forced a more straightforward save from Davis after neat combination with Adam Johnson.
With just over half of the first period elapsed, Ramirez began to pull some strings in the hosts' midfield. The Uruguayan first forced Simon Mignolet to parry away hastily, before firing just over with another vicious left-footed effort.
It was O'Neill's side that opened the scoring just before the half-time break, though. Johnson delivered a dangerous low cross from the left, which intended-target Sessegnon sliced horribly. However, fortunately for the visitors, it fell to Fletcher's feet and the Scot had no trouble tucking the ball away.
The second half started with a strong, early chance - Lambert shooting just over for Saints - however it was, again, largely uninspiring from both teams. Half chances saw Johnson blaze over for the visitors and Jose Fonte's header deflect wide for Adkins men, but there was little cutting edge.
Things got scrappy as the half proceeded, Johnson being forced off after receiving a tough tackle and other niggling fouls while trying to break up play, as both sides' forwards fed on scraps.
Sunderland, however, seemed content to soak up the sporadic Southampton pressure, and held on for a vital victory that pushes them further away from the drop zone, while Saints, despite late chances for Ramirez and Guly do Prado, have just goal difference to thank for their own avoidance of the bottom three spots.