Pilgrims front man Luke Jephcott looked liked he had handed the visitors all three points with two second-half strikes.
However, substitute Curtis and the recalled Bolton denied them a telling win at Fratton Park as the Blues rescued an unexpected point.
Irishman Curtis deserves credit for the comeback, with his persistence getting Pompey back in the game.
Meanwhile, Bolton was equally important with his header three minutes from time earning the draw.
Here’s how our chief sports writer, Neil Allen, rated their performances – plus those of their Pompey team-mates.
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9. Michael Jacobs - 7
(Replaced by Ronan Curtis on 59 minutes): Worrying departure with apparent knee injury. Photo: JPIMedia
10. Ellis Harrison - 6
(Replaced by Harvey White on 69 minutes): Put himself about and caused problems without looking like scoring. Photo: JPIMedia
11. John Marquis - 5
Commitment undoubtedly there but struggling for form at present. Photo: JPIMedia
12. Ronan Curtis - 8
(Replaced Michael Jacobs on 59 minutes): Excellent energy inspired fightback. Photo: JPIMedia