The Rockies got 11 extra-base hits, making things easy for Jordan Lyles (5-0). He struck out eight in six innings and left with a 10-2 lead.
Alfredo Simon (4-2) was tagged with a season-high eight hits and five runs in three innings.
Blackmon led off the game with his eighth homer of the season and Dickerson followed with his third. It was the first time in team history that the Rockies had hit a pair of home runs to start a game.
Joey Votto, who hit a game-winning homer for the Reds in the ninth inning Friday night, hit his sixth shot in the second.
The Rockies started to pull away with a three-run third, beginning with Dickerson's double. Arenado's double set up Morneau's eighth home run.
Blackmon and Dickerson hit RBI doubles in the fourth.
Dickerson's second homer was a two-run shot that sailed 433 feet into the right-field seats in the sixth. Tulowitzki followed with his 11th homer of the season and second in two nights, a 386-foot shot into the left-field seats.
Blackmon's leadoff home run was the third of his career and second in five days. He led off Colorado's 12-1 win over Texas on May 5 with a homer. ... The Reds activated LHP Aroldis Chapman from the 15-day disabled list and optioned RHP Curtis Partch to Triple-A Louisville before the game. Chapman had missed the entire season after being struck in the face by a line drive in a spring training game on March 19 and undergoing surgery. ... Despite doubling as a pinch hitter on Friday night, Reds CF Billy Hamilton missed his seventh consecutive start because of sprained knuckles on two fingers of his left hand. Manager Bryan Price wanted to make sure Hamilton is 100 percent, he said. "You can expect him to be in there [Sunday], I think it's safe to say," Price said.
Copyright by STATS LLC and The Associated Press
CINCINNATI, OH - MAY 10: Alfredo Simon #31 of the Cincinnati Reds pitches to the Colorado Rockies in the first...