When it ended in 1939 he played for SD Deusto (Bilbao), a team that won a national amateur championship that year.
After the civil war, Athletic Bilbao was forced to rebuild their team almost from scratch, because most players who had proclaimed league champions in 1936 were now retired or in exile.
Bertol was one of the key pieces in that team, especially between 1942–43 and 1948–49 seasons, although his role was in second place to the stars of the club, namely the forwards and the goalkeeper Lezama.
Bertol's honours included a league title (1942–43), two runner-up finishes (1940–41 and 1946–47), two Cup wins (1944, 1945) and two losing finals (1942 and 1949).
His international debut was on 26 January 1947 in a friendly against Portugal (4–1 defeat), and his second and final match was played in 1948 against Switzerland, a 3–3 draw.