Striker Abdul Aziz Yakubu scored the only goal as Estoril nicked a slim 1-0 win at Benfica II on Sunday in the Portuguese Segunda Liga.
The 19-year-old put the ball at the back of the net in the 65th minute to seal the points on the road.
Yakubu has now registered two league goals in four matches.
He joined Estoril from Portuguese Liga side Vitoria Guimaraes.
Estoril have now won their last three matches and have improved to third place on the standings.