BEIJING, Aug. 19 (Xinhua) -- None of the matchup of the quarter-finals will be an easy one, even to the undefeated United States, when the men's basketball medal round takes into action on Wednesday.

    The U.S. (5-0) will face Australia as the group leaders from the preliminary round in a late-night show, with the winners to meet the qualifiers from a game between defending champions Argentina and world runners-up Greece.

    Australia, which stunned the other group leaders Lithuania 106-75 on Monday, will give a hard time to the U.S., which beat them 87-76 in a warmup earlier this month.

    Argentina will have a tough test from Greece, and if they make it through, the U.S. are too powerful to be conquered.

    Lithuania will take on the hosts China in the afternoon action. China had proved to be a big challenge to any top teams though their best marks at the Olympics were the eighth placing.

    World champion Spain will meet the sharp-shooting Croatia on Wednesday and will play the winners of the match between Lithuania and China if they advance.