Match ends, Sunderland 1, Portsmouth 0.
Chris Maguire's stunning volley handed Sunderland the initiative after the first leg of their League One play-off semi-final against Portsmouth.
The second-half substitute fired home Pompey defender Matt Clarke's attempted clearing header first time from 15 yards within four minutes after coming on to give the Black Cats a precious lead.
Sunderland then had to dig in to defend their advantage as defender Alim Ozturk was shown a straight red card for bringing down Gareth Evans.
Evans hit the bar with the resulting free-kick as Pompey went in search of an equaliser.
But Maguire also hit the post with another effort as Sunderland held on to take a slender advantage to Fratton Park for Thursday's second leg (19:45 BST).
It was Sunderland's first victory over Portsmouth in four meetings this season, but it was watched by the Stadium of Light's lowest attendance of the campaign - the crowd of 26,610 being 14,519 less than when the sides faced each other in the league last month.
The home side's cause was not helped by the loss of influential former Celtic and Republic of Ireland winger Aiden McGeady to injury in the warm-up.
However, his replacement, Lynden Gooch, was central to Sunderland creating the better of what few chances there were in a scrappy first half.
Two of them fell to Charlie Wyke, with the striker first unable to direct his header on target from Gooch's cross before firing over when stretching on the half-volley 10 yards out.
Gooch then forced a comfortable save out of Portsmouth keeper Craig MacGillivray with the first period's only effort on target.
Sunderland upped the tempo after the break and it needed a remarkable save from MacGillivray to keep Pompey on terms, the keeper somehow turning George Honeyman's close-range header over the bar off his face.
MacGillivray was helpless to keep out Maguire's strike but the advantage seemed to swing back Portsmouth's way when Ozturk was adjudged to have denied a clear and obvious goalscoring opportunity when Evans' touch had appeared to take him away from goal.
But Kenny Jackett's side were unable to find an equaliser against Sunderland's 10 men and will now need to turn the tie around in their home leg.
Sunderland boss Jack Ross:
"My reaction at the time (of the sending off) was that it was impossible to tell at first if it was a foul, but my only criticism was if it was a goalscoring opportunity.
"I think (Evans') touch has taken him the wrong side of the box. Having watched it again, I am still of that opinion.
"We will appeal on that basis - I don't think it was clear and obvious. I may always say that, but I take a balanced view on it."
"You would take any sort of advantage before the game going into the second leg, and particularly with how the game panned out, we are pleased."
Portsmouth manager Kenny Jackett told BBC Radio Solent:
"We're 1-0 down at half-time, but with the second leg to come, I don't think that's too much of a disaster on the balance of it.
"We have to make sure the chances we do create, we're more clinical with.
"I thought we were pretty solid up to half-time and in that pretty impressive period they had for 15 minutes in the second half, they scored a great goal which our goalkeeper had no chance with.
"Although we had pressure against 10 men, we couldn't get close enough to them to force shots on target, the best chance we had being the free-kick that hit the crossbar.
"The whole night was like that really where we had some good situations and control, but couldn't really find the goals once we got up to the final third."
- 5OzturkBooked at 67mins
- 11GoochSubstituted forDunneat 70'minutes
- 10HoneymanBooked at 82mins
- 17MorganSubstituted forMaguireat 58'minutes
- 11CurtisSubstituted forBogleat 69'minutes
- 9HawkinsSubstituted forSolomon-Otaborat 69'minutes
- Andy Woolmer
- Shots on Target
Second Half ends, Sunderland 1, Portsmouth 0.
Bryan Oviedo (Sunderland) wins a free kick in the defensive half.
Foul by Gareth Evans (Portsmouth).
Bryan Oviedo (Sunderland) wins a free kick on the left wing.
Foul by Omar Bogle (Portsmouth).
Max Power (Sunderland) wins a free kick in the defensive half.
Foul by Christian Burgess (Portsmouth).
Foul by Chris Maguire (Sunderland).
Viv Solomon-Otabor (Portsmouth) wins a free kick on the left wing.
Charlie Wyke (Sunderland) wins a free kick in the attacking half.
Foul by Matthew Clarke (Portsmouth).
Corner, Portsmouth. Conceded by Luke O'Nien.
Delay over. They are ready to continue.
Delay in match Ben Close (Portsmouth) because of an injury.
Attempt saved. Omar Bogle (Portsmouth) left footed shot from the centre of the box is saved in the top left corner.
Attempt missed. Ben Close (Portsmouth) header from the centre of the box misses to the right. Assisted by Omar Bogle with a cross.
George Honeyman (Sunderland) is shown the yellow card for a bad foul.
Foul by George Honeyman (Sunderland).
Viv Solomon-Otabor (Portsmouth) wins a free kick in the defensive half.