Benfica striker Miklos Feher has been pronounced dead after collapsing during his side's 1-0 win at Vitoria Guimaraes.
The Hungarian international collapsed in injury time as his side scored the winning goal.
After being treated for some time on the pitch he was taken to hospital as his team-mates and coach Jose Antonio Camacho wept. He collapsed just after being booked in injury time by the referee. The 24-year-old was taken to Guimaraes hospital where efforts to revive him continued and the game was then concluded after he was removed unconscious.
However, the Portuguese media, citing a Benfica spokesman, reported that the player has now been pronounced dead.
Although rare, Feher's death is not unprecedented and last summer Cameroon international Marc-Vivien Foe died after collapsing on the field during his team's Confederations Cup match with Colombia in France.
An autopsy has been scheduled for Monday on the player but media reports in Portugal are already suggesting that a cardiac problem is seen as a likely cause.