The Argentina manager, whose team face Germany in Cape Town on Saturday, launched an attack on compatriot Hector Baldassi's refereeing of Spain's 1-0 second-round win over Portugal.
"Baldassi didn't let Portugal reach (Spain's box), I think every 50-50 decision went Spain's way, it was horrible refereeing," Maradona told a news conference at Green Point Stadium on Friday.
Maradona said he knew Baldassi well, they spoke often and he respected the official.
He gave him no quarter, however, over his decision-making in the win that sent Spain into Saturday's other quarter-final against Paraguay in Johannesburg.
"(David Villa's) goal was offside ... That was an offside as big as this World Cup," Maradona said.
"Baldassi was very poor. The (foul in the) sending off (of Portugal's Hugo Almeida) was non existent."
Argentina and Germany were involved in two controversial decisions in the second round of the tournament.
Carlos Tevez was offside when he put Argentina ahead in their 3-1 win over Mexico, while Germany's 4-1 victory over England came after the English were denied an equaliser despite a Frank Lampard shot crossing the line.
Maradona played down Germany's attacking strengths by saying England had made things easy for Germany, allowing them to hit them on the counter-attack.
"Let's not get into our heads the 4-1 against England, let's not swallow the lie. England eased Germany's path and Germany profited," he said.
"England's goal the other day was very clear, as clear as the goal the linesman gave to England in the 1966 final (against Germany).
"If they can't see, why are they here? ... These things will happen in football until goal-line technology is introduced."
