The reigning European Champions got off to a flier in the opening thirty-five minutes, thanks to goals from André Silva and João Mário.
However, their dominance was unacceptably short-lived as the North African side hit back through Badri and Ben Youssef.
The opening exchanges in this friendly encounter were far from affable as both sides were on the end of several rash challenges.
Portugal started to assert their authority on the game as the half wore on, yet despite their dominance in possession the lack of cohesion amongst the back four will have concerned Fernando Santos.
Midway through the first-half Portugal eventually made the breakthrough.
Bernardo Silva fed Ricardo Quaresma out on the right and the Besiktas winger whipped in a ball to the far post where André Silva headed home past a helpless Hassan. Twelve minutes later it was 2-0.
Bernardo Silva, who has come on leaps-and-bounds this season at Manchester City, whipped over a corner which was headed away to the edge of the area. João Mário was waiting and the West Ham loanee rifled a missile-like shot into the top left-hand corner of the net.
Tunisia pulled a goal back minutes later. Portugal’s back line had looked shaky and their lack of cohesion was all the more prevalent on this occasion. A flowing move saw the African nation switch the ball to the left side of the box where Sliti fed a touch through to Badri to finish impressively from the edge of the box. As play resumed in the second-half Portugal began on the front foot once more.
Fifty-five minutes in they were a whisker away from scoring their third of the evening through Bernardo Silva. Manchester City’s playmaker weaved his way along the edge of the box, before striking a low effort that came back off the post, with Hassen then brilliantly denying João Mário. Silva then had another chance but this time struck his effort high and wide.
A rash of substitutions were made and the game eventually lost its exciting flow, particularly amongst the Portuguese. Tunisia began to get into the game more and were rewarded in the sixty-fourth minute.
Anthony Lopes punched away a Tunisia free-kick but the ball found its way back to Maaloul, whose elegantly curled cross was met by Ben Youssef to tuck home the equaliser.
As the game progressed and more substitutions were made Portugal’s tactics and game plan fell apart.
Tunisia’s two goals were entirely deserved as they proceeded to cause the Portuguese defence and midfield numerous issues with their direct counter-attacks.
Portugal now face Belgium, another of England’s World Cup opponents, at Brussels’ Heysel Stadium on Saturday, before completing their warm-up games against Algeria at the Estádio da Luz on 7 June.
The serious business in Russia gets under way on 15 June with the all-Iberian clash between Spain and Portugal.