Pompey picked up a point in their opening Papa John's Trophy group stage match at Crawley.
The contest finished 2-2, with the visitors missing out on a bonus point after being beaten 6-5 in a shoot-out.
Clark Robertson had earlier cancelled out Dom Telford's penalty and Dane Scarlett gave Danny Cowley's men the lead before David Bremang levelled from the spot in stoppage-time.