Andrew Surman saw his ferocious effort smash against the upright in the fourth minute of stoppage time as the Saints pushed hard for a winner.
But it was Blackpool who took the initiative in the opening 45 minutes with a number of efforts that could have put them well in front.
It was an innocuous looking challenge by Jan-Paul Saeijs on DJ Campbell on 19 minutes that saw the referee point to the spot. Campbell sent Southampton keeper Kelvin Davis the wrong way, slotting the ball into the left-hand corner of the net.
Despite a couple of efforts from captain Jason Euell, including a fierce header which flew inches wide, Blackpool looked the most likely to continue scoring.
Campbell went close again with a mazy run into the box on 38 minutes, and almost doubled his side's lead with an acrobatic bicycle kick which was tipped over the bar just before the break.
The visitors were forced to rely on David McGoldrick for their chances. However, his best effort, when he snuck into the box on 39 minutes, saw him scuff his side's best chance straight at Paul Rachubka.
The second half saw a resurgent Southampton pile the pressure on the home side. Former Seasider Simon Gillett went close on 51 minutes and Morgan Schneiderlin also had a good effort saved.
McGoldrick made up for his earlier miss on 69 minutes when he slotted the ball past Rachubka after strolling through a static Blackpool defence.
It was Southampton who enjoyed the better of the play towards the end of the match with Blackpool forced to defend wave after wave of attacks.