Pompey won the game at Fratton Park 2-0 courtesy of two second half goals from French striker Frederic Piquionne but Blues were denied what McLeish described as a 'lifeline' when the referee's assistant failed to notice that Ridgewell's 80th minute header had clearly crossed the goal line before a grounded David James scooped the ball to safety,
"We should have had a lifeline with a perfectly legitimate goal but unfortunately it wasn't to be," McLeish said.
"It would have given us a lifeline and I wouldn't bet against my team coming back if we got that goal. They've done that this season.
"You would expect an official at this level to see that. They do the fitness tests and part of that is the vision side of things. It's a shame the guy missed that, I'm sure he will be hurting about it.
"For an hour I thought we were the better side, our build-up was composed and we looked in control.
"But we did not make enough chances up front and when we did, we did not take them."