Pfister led Ghana to a famous win in the 1991 FIFA U-17 World Championship. The Championship was held in the cities of Florence, Montecatini Terme, Viareggio, Massa, Carrara, and Livorno in Italy between 16 August and 31 August 1991. Ghana finished second to Spain in their group and progressed to the Quarter-finals where they beat Brazil 2–1 with goals from Mohammed Gargo and Nii Lamptey. After a 0–0 draw with Qatar in the Semi-finals, Ghana won 4–2 in a penalty shoot-out, lining up a final against Spain. On 31 August 1991, Ghana beat Spain 1–0 in the World Cup final in Florence, Ghana's first title.