San Diego is 10-3 against Cincinnati in the last three seasons, its best record against any team.
The game marked the beginning of the Reds' biggest weekend of the season. Hits king Pete Rose will be inducted into the Reds' Hall of Fame and his No. 14 will be officially retired. His number was cut into the grass in center field for the series.
J.C. Ramirez (1-3) gave up Norris' 10th homer run for a 6-4 lead.
Christian Friedrich (4-2) allowed four runs in five innings, including Adam Duvall's two-run homer. Duvall became the fourth player in the majors with 21 homers, joining Colorado's Nolan Arenado, the Chicago's Todd Frazer and Baltimore's Mark Trumbo.
Fernando Rodney remained perfect in 16 save chances.
