Tony Mowbray's side went into the clash at Fratton Park on the back of a confidence-boosting win at Derby and backed that up with a thoroughly-deserved point.
Portsmouth were left frustrated as they wasted a string of chances to beat goalkeeper Paul Smith. Joel Ward could have tested Smith but his headed effort lacked the power and direction to cause any alarm.
They did come within a whisker after 20 minutes, though, as another header from Hermann Hreidarsson rattled the bar as he latched onto David Cotterill's free-kick.
Smith did do well to keep Pompey at bay as the game reached its final stages, punching away a Dave Nugent header as it threatened to find a way through a crowded area.
But Marvin Emnes - on for the injured Leroy Lita - nearly snatched victory for the visitors as his drive from the left side of penalty area brought another crucial save from Jamie Ashdown.
Source: PA
Source: PA