That’s significantly less than the Black Cats’ average attendance this season as the countdown to play-off battle gathers pace.
Sunderland have approximately 24,000 season ticket holders with their lowest league attendance this term 27,850 - and their average gate topping 30,000.
But the take-up for the game has been beneath that figure, although the club are hoping there will be a late rush to snap up seats.
The number tickets sold doesn’t factor in away fans or hospitality guests.
There are still tickets left from Pompey’s allocation for the game, with the Blues given 2,000 seats.
The match will be televised on Sky Sports tomorrow night and will be the fourth time the sides have met this term - the last being the 1-1 draw at the Stadium of Light two weeks ago.