A solitary goal from Jamille Matt ended Brackley Town’s dreams in the Emirates FA Cup.
Saints gave it everything and only the woodwork denied them a first half equaliser.
Matt settled Blackpool’s early nerves when he gave them a sixth minute lead, heading home from six yards after he got on the end of an effort from Brad Potts.
That was the first time Saints had been behind in this season’s competition and it proved crucial.
The visitors came close to a quick reply when Lee Ndlovu saw his close range effort deflected just wide of the post.
But, boosted by the early goal, Blackpool had the better of the opening period.
Potts tested Laurie Walker moments later from a quick break and then saw the Saints keeper turn another effort around the post while in between Bright Samuel had a shot blocked.
Samuel fired over from just outside the box as Blackpool continued to look for the crucial second goal before the break.
Kyle Vassell’s shot from the edge of the area was saved by Walker before Saints began to get into the contest.
The visitors found it difficult to create openings but they enjoyed their best spell just before the interval and James Armson headed wide from their first opportunity.
And Saints almost snatched an equaliser in first half stoppage-time when Glenn Walker’s low cross was thundered against the underside of the bar by Blackpool’s Clark Robertson under pressure from Ndlovu.
That gave Kevin Wilkin’s side a boost for the second half and after the restart they enjoyed their best spell of the tie.
Armson twice went close with efforts that went wide while Ndlovu was denied by Sam Slocombe after breaking clear.
Walker denied Vassell from a tight angle but Blackpool found it more difficult to create chances in the second half.
Saints piled on the pressure in the closing stages and Tom Aldred had to head clear after Slocombe was unable to hold on to the ball under pressure.
Substitute David Moyo was unable to turn in Shane Byrne’s free-kick deep into stoppage-time and it was Matt’s early goal which sent Blackpool through and Saints out as their excellent FA Cup run came to an end.