The first half was a dire affair with neither side able to dominate.
Loan star Jermaine Pennant, who is expected to agree terms this week for a close season move from Arsenal, was not as positive as usual and the winger's lack of flair was reflected in Blues' general performance.
Lomana LuaLua went close to giving Pompey a great start with a header which flew just wide from a Gary O'Neil cross, but that was the only occasion in the first period that Blues goalkeeper Maik Taylor was in any trouble.
Blues' goal attempts were little better. Stan Lazaridis twice tried his luck but neither effort was on target and Pompey shot-stopper Jamie Ashdown also had little work to do.
Fortunately the second half was much brighter as both teams displayed more urgency, as highlighted when O'Neil jinked his way inside only for Taylor to parry his low shot.
Seconds later Linvoy Primus cleared an Emile Heskey header off the line with Ashdown stranded.
Steve Bruce was obviously far from happy with Blues inability to break through Portsmouth's defence and made a double substitution, sending on Clinton Morrison and Julian Gray for Walter Pandiani and Lazaridis on the hour.
But there was no immediate improvement and Portsmouth hung on to gain a valuable away point despite some desperate attempts from Blues to break the stalemate.
Man of the match. Kenny Cunningham. In a game dominated by the two defences Cunningham was the pick of the players on show. Diomansy Kamara and Lomana LuaLua rarely troubled the Irishman and Pompey were able to create few chances.