Brazilian striker Alexandre Pato, whose early performances prompted comparisons with Ronaldo and Pele, has failed to live up to his reputation at the Olympics and now finds himself on the sidelines.

　　The AC Milan player arrived in China as one of the big names of the Olympic tournament alongside Ronaldinho and Lionel Messi but has barely made a mark, scoring one goal in three group games and offering few attacking options.

　　He then lost his place to Rafael Sobis for the 2-0 quarter-final win against Cameroon and, judging by the comments of coach Dunga, is unlikely to regain it very soon.

　　The 18-year-old, who has already seen action with Milan and Brazil, was expected to thrive in the Olympics, an under-23 tournament with three over-age players allowed per team.

　　But Dunga’s praise of Sobis, who helped Internacional win the South American Libertadores Cup in 2006, appeared to be just as much veiled criticism of Pato.

　　“I opted for Rafael Sobis because of the way he has improved in training and during the games,” said Dunga, whose team face Argentina in Tuesday’s semi-final.

　　“Rafael is a player who can survive tough marking, who opens up spaces, who can make diagonal runs and doesn’t get caught offside.

　　“He gets involved in training and he is used to these types of games in the Libertadores.”

　　Pato, whose nickname means Duck and is taken from his home town of Pato Branco, made a flying start to both his professional and international careers.

　　He scored after less than two minutes of his first professional game as a 17-year-old for Internacional against Palmeiras in the Brazilian championship in 2006 and set up two more as he inspired his team to a 4-1 win.

　　In his international debut against Sweden 16 months later, he needed only 10 minutes to score the winning goal after coming on as a substitute.

　　But he was disappointingly ineffective in Milan’s Champions League elimination by Arsenal and was on the losing side in Brazil’s friendly defeat by Venezuela in June.

　　“He needs a bit of polish, he needs to know how to face tough marking and to get free of it,” said Dunga.