The flamboyant Count of Montefusco took San Francisco by storm in the mid-1970s. Reminiscent of Dizzy Dean, he made predictions and backed them with sensational performances. He made a sparkling debut with the Giants in September of 1974, defeating the arch-rival Dodgers in relief and hitting a home run in his first ML at-bat. In 1975 the fastballer predicted a shutout over the Dodgers and then delivered, 1-0. His 1975 record of 15-9, with a 2.88 ERA and the second-highest strikeout total in the league (215), earned him the NL Rookie of the Year Award. In 1976 he was 16-14, with a 2.84 ERA and a NL-topping six shutouts. He no-hit the Braves, 9-0, on September 29.

As injuries affected his performance, his antics lost their charm. A fistfight with Giants manager Dave Bristol hastened his exit from San Francisco. In a brief 1983 comeback, he had a combined 14-4 mark with the Padres and Yankees.