Two Argyle goals in a torrid few minutes for Stags have given Adam Murray’s men a mountain to climb.
There was an early chance for the hosts, Ryan Brunt shooting wide under pressure from Chris Beardsley.
Craig Tanner then shot wide from distance, and at the other end, Mal Benning carried the ball a long way before blasting just over.
Ryan Tafazolli had to be sharp to clear, when Gregg Wylde found Brunt in the area.
Pressure was mounting on Stags, and finally took its toll when Wylde shot from 25 yards out and although Scott Shearer got a hand to it he couldn’t keep it out.
Almost immediately, Plymouth attacked again and won a spot-kick, Krystian Pearce tangling with Carl McHugh, Brunt converting for a 2-0 lead.
Things could have got even worse, but Brunt was denied by the post.
And the woodwork then kept Mansfield out, Tafazolli the man coming close with a looping header.