Complex sentence: The future world champion beat his Italian opponent by 5½-3½, but Dubois did win several other matches that same year against Cornelius Bonetti (11½-1½) and against Valentine Green--the first he won 5-0 and the second 5½-½.
Split into simpler sentences: The future world champion beat his Italian opponent by 5½-3½. But Dubois did win several other matches that same year: against Cornelius Bonetti (11½-1½) and against Valentine Green; the first he won 5-0 and the second 5½-½.