The Blues had the chance to maintain their 100-per-cent winning start to the League One season when Gassan Ahadme was fouled in the penalty box 14 minutes from time.
However, substitute Shaun Williams failed to make the most of his chance from the spot as keeper Pontus Dahlberg saved his tame effort.
9. Gassan Ahadme - 6
Influence grew after the break and earned penalty with lovely touch.
10. Ronan Curtis - 6
Busy and committed but couldn’t grab game by scruff of the neck as he would’ve liked.
11. John Marquis - 5
(Replaced by George Hirst on 74 minutes): Toiled away without success and will rue not making more of header as Dahlberg made fine save.
12. Shaun Williams - 5
(Replaced Joe Morrell on 59 minutes): Terrible penalty lacked conviction and cost Pompey dear.