Marcelo Bielsa felt Marco Estrada's sending off against Spain helped gift Chile's opponents victory on Friday.
Bielsa's men impressed in Pretoria only to be reduced to 10 men when Estrada was handed a second yellow card for a foul on Fernando Torres in the lead up to Andres Iniesta's goal.
Yet, despite a 2-1 loss against Spain, Chile advanced from Group H as runners-up, and will face Brazil in the last 16.
"It was even until the ejection," said Bielsa "Spain's goals weren't just down to their own merit.
"The first 40 minutes were balanced in possession, in control and goal chances," Bielsa said. "Evidently, afterwards it was a different match.
"We also instinctively felt that to qualify was the prime objective."
Chile midfielder Arturo Vidal, meanwhile, is already looking to Monday's meeting with five-times World Cup winners Brazil.
"We know Brazil are candidates for the title but we have our qualities too," said Vidal.