John Boye's own goal gifted Portugal a 1-0 lead over Ghana at halftime in their final Group G game at the World Cup on Thursday, giving Cristiano Ronaldo's side hope of reaching the knockout stage.
Ronaldo had struck the crossbar with an over-hit cross and had a gilt-edged chance saved before Miguel Veloso's left-wing cross was sliced into his own net by Boye in the 31st minute.
Portugal and Ghana both need to win to stand any chance of beating either Germany or the United States to a top-two finish.
Playing as a central striker, Ronaldo was a lively presence at the Estadio Nacional, with the Real Madrid superstar also having two fierce shots saved by Ghana goalkeeper Fatawu Dauda.
Asamoah Gyan squandered Ghana's best two openings.