Portugal coach Paulo Bento suggested the referee was biased in favour of Germany after his side had a penalty awarded against them and a player sent off in their 4-0 World Cup defeat on Monday.

"These were the two things that seemed to show bias and they were both decisive," he told a news conference of the penalty decision after 12 minutes and the 37th-minute sending-off of defender Pepe in the Group G opener.

Germany went 1-0 ahead through a Thomas Mueller penalty after Mario Goetze wriggled away from Joao Pereira and was hauled down.

Pepe was sent off for shoving his forehead into Mueller's before the end of the first half.

"The penalty was forced," added Bento, seemingly suggesting that Mueller, who was sitting on the turf when an incensed Pepe came back to accost him, was guilty of instigating the situation that had the Portugal defender red carded by Milorad Mazic of Serbia.

"I don't know if he was sent off because of his reputation," said the coach.

"I'm not saying it was the referee's fault only," he added. "We did make mistakes, not only in our defence but also in the sharpness of our attack.

"For us the game was over by halftime and although we tried a bit in the second half, we didn't show much either. Germany controlled the game by holding the ball and the two decisions threw us out of balance."

Bento said he faced having to make several changes in the next match against the U.S. in Manaus on Sunday with Pepe suspended and Fabio Coentrao and Hugo Almeida going off injured on Monday.

"The initial prognosis does not look good," he said of their chances of appearing in the next game.

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