While the responsibility for Wimbledon's winning goal must be borne by the usually dependable Paul Jones, one wonders whether there is something in the Saints' collective psyche that is rendering them incapable of inflicting defeats on sides in trouble.
The Dons had not scored for over five and a half hours before the start of the game, and until the 38th minute, when Jones ran out of his goal and fell over attempting a routine clearance, they had shown few signs of ending the drought.
Carl Leaburn, surprised to find himself gifted the ball, remained composed to score from a tight angle.
"We have had to work out tactically how we can win games 1-0 and have carved out a lot of valuable victories," said Joe Kinnear, the Wimbledon manager.
It is fortunate for Kinnear that his side's defensive record away from home is the best in the Premiership, having conceded only 15 goals in 14 games on their travels. "The missing ingredient is a striker who can score 15 goals a season," said Kinnear.
Wimbledon gave a tight defensive performance but there was little attacking or creative play from anyone but Michael Hughes. Nonetheless, the Dons deserved the points, and the win leaves them six points clear of the bottom three and with a game in hand on five of the seven teams below them.
As Wimbledon prepare to meet Everton at Selhurst Park today, Kinnear feels that his young side is more than capable of staying in the Premiership. "Our destiny is in our hands. The pressure builds up on people but you've got to keep your head."
Dave Jones, the Southampton manager, admitted his team had underperformed, but did not seek to blame his goalkeeper's error. "The keeper has been fantastic and has made one mistake and got punished for it.
"There are lots of games where he has kept us in it to be fair," said Jones, who has built a side who can appear, albeit sporadically, to have great potential.
However, while the Saints have beaten Manchester United, Liverpool, Chelsea and Blackburn in recent months to reach mid-table, they have now lost to Barnsley, Sheffield Wednesday and Wimbledon in the past month.
"We just didn't perform to the best of our ability today," said Jones. It is tempting to believe that his team may know only too well what fighting relegation is like, and either through relief at not being involved, or sympathy for those more deeply embroiled, they were simply not committed enough.
Goal: Leaburn (38) 0-1.
Southampton (4-4-2): Jones; Benali (Monkou, 82), Dryden, Lundekvam, Dodd; Beresford, Richardson (Williams, 57), Palmer, Hughes; Ostenstad, Hirst (Davies, 57). Substitutes not used: Gibbens, Moss (gk).
Wimbledon (4-4-2): Sullivan; Thatcher, Blackwell, Perry, Cunningham; M Hughes, Roberts, Earle, Ardley; Gayle (C Hughes, 69), Leaburn. Substitutes not used: McAllister, Clarke, Euell, Heald (gk).
Referee: M. Reed (Birmingham).
Booking: Southampton: Lundekvam.
Man of the match: M Hughes.