Cristiano Ronaldo headed the only goal as Portugal recorded their first win at the Confederations Cup by beating hosts Russia.
Ronaldo, whose future at club Real Madrid is in doubt, connected with Raphael Guerreiro's cross in the eighth minute to send Portugal top of Group A.
Russia goalkeeper Igor Akinfeev, earning his 100th cap, saved well from Andre Silva early in the second half.
Mexico can go top of the group with a win over New Zealand later.
Russia missed two late chances to salvage a draw as Georgy Dzhikya headed over and Fedor Smolov floated an effort wide.
Ronaldo, 32, reportedly wants to leave Real Madrid after being accused by Spanish prosecutors of tax fraud, something which he denies.
The forward, who started Portugal's 2-2 draw with Mexico on Sunday, signed a new five-year contract in November but has been linked with a return to Manchester United.