By Arturo Silva EAST RUTHERFORD, New Jersey (Reuters) - Mexico coach Miguel Herrera has denied his team had received help from the referee to beat Costa Rica 1-0 after extra time and reach the CONCACAF Gold Cup semi-finals. Midfielder Andres Guardado converted from the spot in the 124th minute of Sunday's quarter-final at the MetLife after Guatemalan referee Walter Lopez awarded Mexico a controversial penalty for an alleged push on striker Oribe Peralta. Lopez was set to give Costa Rica a goal kick after Peralta was unable to connect with an attempted header but changed his mind and pointed to the spot after his American assistant Eric Boria flagged for a penalty by Costa Rica's Roy Miller. More...