After a one-year hiatus, Fontenot returned to the playoffs as part of a Giants team that won the NL West. After pinch-hitting in Game 2 of the NLDS against the Braves, he started Games 3 and 4 at third base. He had a triple against Tim Hudson to start the second inning of Game 3 and scored the Giants' first run in their eventual 3–2 victory. The Giants won the series in four games, advancing to the NL Championship Series (NLCS) against the Phillies. Fontenot started the first two games of the series at third base, but after only recording one hit in seven at bats, he was used merely as a pinch hitter in his other two appearances in the series. He got a hit in his only at bat of Game 6, a 3–2 series-clinching victory that sent the Giants to the to the World Series against the Texas Rangers. Fontenot had the unusual distinction of being credited with a game played in the World Series without recording a plate appearance or a play in the field. In the eighth inning of Game 2, the left-handed-hitting Fontenot was announced as a pinch-hitter with the Giants leading the Rangers, 6–0. The Rangers replaced right-handed pitcher Mark Lowe with the left-handed Michael Kirkman, prompting the Giants to replace Fontenot with the right-handed Aaron Rowand, who tripled. Fontenot went on to become a World Series champion as San Francisco won the series in five games, their first World Series victory since 1954.