Seongnam, South Korea:Costa Rica coach Alexandre Guimares on Wednesday complained the refereeing in his team's opening match against China was too tight. "Some of the calls were a bit over the top," he said, annoyed that four of his players received yellow cards in their Group C match Tuesday. Mauricio Solis, Luis Marin, Ronald Gomez and Walter Ceno were all cautioned for rough play as Costa Rica downed China 2-0, spoiling the World Cup debut of the Chinese. Guimaraes said he appealed to Gomez to help soften up Greek referee Kyros Vassaras. Gomez plays in Greece's first-division, for OFI Crete, and he hoped speaking some Greek might help him gain some favor. But "he complained that (Luis) Marin had already committed a number of fouls,'' Gomez said. Despite the complaints, Gomez said that Vassaras was one of the best referees in Greece. With three points, Costa Rica is atop Group C, tied with four-time World Cup champions Brazil. The Brazilians face the Chinese on Saturday, and Costa Rica takes on Turkey the following day.