And the former Blues chairman is confident Kenny Jackett's men will avoid a third successive play-off campaign by finishing in League One’s automatic promotion spots.
Pompey's hopes of making it out of the third tier suffered a setback this week following home defeats to current top two Lincoln and Hull.
Those back-to-back losses have pushed the Blues down to fifth, leaving them seven points off the summit.
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They also currently find themselves four points adrift of second-placed Hull, although they do have a game in hand on Grant McCann's side.
But for McInnes, who was Pompey chairman for four years prior to Tornate’s takeover in August 2017, said there is no cause for concern.
He was at the club when Paul Cook led the Blues to the League Two title in the 2016-17 season.
And McInnes has seen enough within the squad so far this term which suggests Pompey can finally return to the second tier after a nine-year hiatus.
The former Blues chief said: ‘I’m absolutely convinced of it (automatic promotion).
‘There have been perennial finishes in the play-off zone.
‘This is the season where they’ve got to either nab position one or two because I think the nerves would be so jangled by going into yet another play-off scenario, that I’m not sure anybody really wants to see that.
‘I think they can and I think they will (reach the Championship). If you look at the squad they’ve got, if you look at the depth of squad they’ve got, and the fact that they’re able to beat the best on a good day.’
Pompey remain forced to play matches behind closed doors at present amid the Covid-19 epidemic.
McInnes believes the Fratton faithful can be worth 'up to 10 points' a season so feels they are a massive loss at the moment.
Yet, with vaccines currently being rolled out across Britain, the former Blues chairman says the potential return of supporters in time for the final few weeks of the campaign could help push Pompey to promotion.
He added: 'We’ve always said and will continue to say that the Pompey fans are very special and probably worth up to 10 points a season.
'I think they’re going to hold their nerve, we hope that towards the back end of the season fans will be allowed back in some shape or form, it was interesting to see when they did have a couple of thousand fans.
‘I think it’ll be the final push to help get Pompey back in the Championship, where we belong.’