DJ LeMahieu and Michael Cuddyer each drove in a pair of runs as the Colorado Rockies took an 8-3 win over the Boston Red Sox in the opener of a two-game set.
Charlie Blackmon, Troy Tulowitzki and Corey Dickerson each hit a solo home run for the Rockies, who had lost four of six coming in.
Tyler Chatwood (8-5) gave up an unearned run on three hits with a walk and two strikeouts over seven innings to take the loss.
"Give a lot of credit to Chatty for the improvement, the strides he's made. Pretty incredible, how far he's come," Colorado manager Walt Weiss said.
Jarrod Saltalamacchia hit a two-run home run for the Red Sox, who had won three of four prior to Tuesday's game. John Lackey (10-13) pitched six innings and gave up four runs on six hits with a walk and five strikeouts.
"I thought John made a couple of mistakes he had to pay for, particularly in a ballpark where you put the ball in the air, it's going to carry," Red Sox manager John Farrell said.
The Red Sox are a game ahead of the Oakland Athletics for the AL's best record.
Blackmon homered to start the first inning, and Todd Helton scored Cuddyer with a single later in the inning for a 2-0 lead.
Tulowitzki homered in the third, while Dickerson went deep in the fourth for a 4-0 lead.
Will Middlebrooks scored in the seventh thanks to a fielding error by Chatwood on a Jackie Bradley grounder to make it a 4-1 game.
A pair of two-run singles, though, from LeMahieu and Cuddyer in the home half of the seventh pushed the score to 8-1.
Saltalamacchia hit his two-run homer in the ninth with David Ortiz on base to account for the final score.
Lackey had won his two previous decisions ... Chatwood won for the first time since July 26, going 0-2 in his previous five starts ... The Red Sox took two games from the Rockies in Boston in late June ... The last time Boston played in Colorado was in 2010.