In another questionable performance by the Saints they went behind to an 85th minute Jermain Defoe goal, shortly after having captain Jose Fonte sent off for bringing down Fabio Borini.
Though the Black Cats were unable to hold on as van Dijk swept home in the dying moments of the match to move the Saints up to 8th in the Premier League table.
Dip in form
After hitting sensational form in January and parts of February the reds have since stalled, reverting to their early season performances that saw Ronald Koeman's men fail to make the most of their chances, and drop points against sides they were expected not to.
The Saints boss made five changes from the side that were well beaten by Bournemouth in midweek, as they looked to turn their fortunes around and get back to winning ways.
Koeman admits he was disappointed with his side’s performance, in his post-match interview he said: “For 85 minutes it was not good or the level I expect from Southampton."
He added, “I think at the moment there is a lack of confidence. At the start of the game they made it very difficult for us as they were very well organised defensively.”
The Dutchman also bemoaned the lack of attacking quality as the Saints missed excellent chances. With Charlie Austin and Shane Long both injured it was left to striker Graziano Pelle to lead the line, the Italian has now failed to score in thirteen games.
The Saints have had more players sent off than any other team in the Premier League, though Fonte’s red card seemed to wake Southampton up according to Koeman, he stated: “When they scored and we had ten against eleven, I think we played the best football with one less player on the pitch."
Koeman concluded, “I am thankful for that, as that is really good character, but we had to do better before that.”
The Saints will now focus on their visit to Stoke City next weekend as they look to get back to winning ways and prove they are in the race for a European spot.