Paul Thirwell admitted Harrogate will need Lady Luck on their side if they are to claim the FA Cup scalp of 2008 winners Pompey.
But Town’s assistant manager reckons it ‘wouldn’t be the biggest shock’ if they were to dump Kenny Jackett’s men out of the competition.
Pompey will be the favourites to come away from Wetherby Road with victory.
The Blues, 13th in the League One table after Tuesday’s 4-1 win against Sol Campbell’s Southend, sit 41 places above National League Harrogate in the English football pyramid.
And having been in attendance at Fratton Park for their victory over the Shrimpers, the former Sheffield United and Sunderland midfielder is under no illusions how tough the tie will be.
But Thirlwell is hoping Harrogate can draw inspiration from previous upsets in the competition.
Havant & Waterloville, Sutton and Wrexham are just a few non-league teams who have etched their names into FA Cup history by causing shocks.
Now Thirwell is hoping Harrogate can follow suit and dump two-time winners Pompey out of the competition.
‘As a smaller club, the opportunity to draw bigger clubs is always there in the FA Cup,’ Thirlwell told the Harrogate Advertiser.
‘We managed to get one really early and Portsmouth would rather have been at home.
‘You've just got to hope the nostalgia of the FA Cup plays into your hands.
‘We went to watch them on Tuesday night (when Portsmouth beat Southend United 4-1) and they're a really good side, so we'll be under no illusions.
‘As we found out going there, it's a long journey whichever way they decide to travel and they'd have wanted a home draw.
‘We're looking forward to it, it's going to be a real big test.
‘It wouldn't be the biggest shock in the world but we're going to have to be at our very best, they're going to have to have an off-day and Lady Luck will need to be on our side.’