Primeiro Agosto kept alive hopes of becoming the first CAF Champions League finalists from Angola by edging Tunisian visitors Esperance 1-0 on Tuesday through a late Luvumbo Pedro goal.
Pedro struck after 80 minutes of the semi-final first leg at Estadio 11 de Novembro in Luanda with a shot from outside the box that Rami Jeridi could only parry into the net.
Before the match-winner, Jeridi had made only one serious save and opposite number Adao Cabaco none in a foul-riddled match that was a poor advertisement for African football.
Esperance captain Khalil Chemmam was sent off in the third minute of stoppage time after receiving a second yellow card for pulling back an opponent just outside the penalty area.
A foul rate of more than one every two minutes meant the match never developed a rhythm and a goalless draw seemed inevitable until substitute Pedro struck.
It was the first away goal Esperance had conceded in the Champions League this season for 595 minutes, with the only other coming in Mauritania last February.
Angolan winger Geraldo was the most creative player on the pitch, and paid the price as he was constantly fouled.
"The refereeing was terrible and it hurt us a lot, but we managed to beat one of the best clubs in Africa," said Serbia-born Primeiro coach Zoran Manojlovic.
"I do not fear playing Esperance in Tunisia, only other factors such as the refereeing. We continue to dream of reaching the final."
Geraldo wasted the best chance of the opening half after evading his marker at the far post as the ball was crossed, but fired wide when he should at least have tested Jeridi.
The Esperance goalkeeper made a spectacular punched clearance soon after half-time off a swerving Geraldo free-kick.
Substitute Haythem Jouini came closest to equalising with a glancing header in stoppage time that flew across Cabaco and just wide.
The Chemmam foul that led to him being red-carded gave Primeiro a free-kick in a threatening position that they failed to take advantage of.
Later Tuesday, record eight-time champions Al Ahly of Egypt host Entente Setif of Algeria in Cairo in the other first leg.
The second legs are set for October 23 with the aggregate winners advancing to a two-leg title decider during November.
At stake will be a $2.5 million (about 2.15mn euros) first prize and qualification for the 2018 FIFA Club World Cup in the United Arab Emirates.