Sunderland have held Vitoria de Setubal to a goalless draw as part of their preparations for the new Premier League season.
The Portuguese side had the ball in the net in the 12th minute through Giovani, but the striker's effort was ruled out for offside.
Pedro Queiros came close to breaking the deadlock moments later, gaining possession in the area following a penalty box scramble, but Costel Pantilimon pulled off a good save to deny him.
Sunderland's best chance to open the scoring in the first half came from a corner, from which Adam Johnson found the head of Valentin Roberge, who forced a save out of Ricardo Batista.
The second half was equally uneventful, but Sunderland did come close to breaking the deadlock shortly after the restart as a long-range effort from Johnson sailed narrowly over the bar.
The winger felt that he should have been awarded a penalty on the hour mark when he went tumbling in the area, but his protests went unheeded and the match finished goalless.