They have released extensive voting data they argue shows Mr Gonzalez defeating Mr Maduro by a significant margin, in line with pre-election polls.
On Wednesday, the New York Times released an analysis showing Mr Gonzalez beat Mr Maduro by more than 30 percentage points.
The news outlet made the conclusions based on partial election results, provided by a group of researchers associated with Venezuela’s main opposition alliance.
The researchers estimated a result of 66 per cent for Mr Gonzalez versus 31 per cent for Mr Maduro, which closely matches the findings of an independent exit poll conducted nationwide on election day.
Maduro said he was “ready to present 100 per cent of the records,” as he addressed journalists outside the Supreme Court of Justice, where he filed an appeal against what he termed an “attack against the electoral process”.
But he voiced outrage at opposition leaders Ms Machado and Mr Gonzalez, saying they “should be behind bars”.
Detentions and ‘forced disappearances’
Protests have erupted across the country, resulting in the deaths of over a dozen individuals and the arrest of more than 1,000.
On Monday, security forces used tear gas and rubber bullets against Venezuelans who flooded the streets chanting “Freedom, freedom!” and “This government is going to fall!”
Ms Machado reported 177 detentions and 11 “forced disappearances”, while Tarek William Saab, the attorney general, stated that over 1,000 people had been arrested during the protests, with some potentially facing terrorism charges.