 In the third round of Central America (end of the zone), Oscar in the first game scored the winning goal against Deportivo Saprissa of Costa Rica at minute 2 of the game and in the lap played in Guatemala he was again the figure of the match by remarking two goals at minutes 14th and 31st that would mean the classification of Comunicaciones and subsequently the consecration of the "crema" team of the CONCACAF 1978 Champions' Cup.He was the top scorer in the league from the 1976 season to the 1979–80 season and holds the record for the most goals scored in a league with 41 in the 1977/78 season.In 1977, Sanchez scored six goals in a 9–0 victory for Comunicaciones against Antigua GFC, tying the historical record of Hugo "Tin tan" Peña of the league in 1961

He also scored five goals in a single game on two other occasions, one that same year against Tipografia Nacional and the other in 1988 against Xelajú MC while playing for CSD Cobán Imperial.