Silvia Martinez, the 61-year-old wife of Oscar Tabarez, was walking home through the city's Carrasco district on Saturday afternoon when the attack happened. A motorbike came speeding up to her, slowed down to allow the pillion passenger to throw what police described as a "corrosive liquid" over her, then sped away.
Martinez ran back home where Tabarez called an ambulance. She was admitted to hospital with burns to 25 per cent of her body, including her face and arms.
Tabarez, who led fourth-ranked Uruguay to the World Cup semi-finals last year, reported the attack to the police, but the motive remains unknown - though Martinez had previously complained about receiving death threats.
"They didn't steal anything. They threw the liquid while slowing down and then sped off," said Montevideo police spokesman Jose Luis Rondan. "They didn't shove her, or insult her, nothing."