Argyle were awarded a spot kick with three minutes remaining only to see Dorus De Vries save Jamie Mackie's effort.
Then controversy, the linesman ruled De Vries had moved early and re-ordered the kick. This time Damien Johnson stepped up but De Vries saved again. Thankfully Johnson was on hand to score from the rebound and a crucial point was earned.
Earlier Swansea had taken the lead through Darren Pratley.
Not the greatest of games but a point that helps the survival effort.
Plymouth need to get a rersult this weekend at home to Leicester. The gap to 21st place is now down to just 5 points.