The Pilgrims were beaten 5-2 by Long Eaton United despite holding a 2-1 advantage with 18 minutes to play, courtesy of Jackson's 37th and 62nd minute strikes, which sandwiched his penalty being saved by home keeper Jake Beresford-Allen.
Benni Wilson scored a hat-trick for the home side, with James Gale and Reece Widdowson also on target.