"This was one of his best outings, right up there, and he just did that against probably the best offensive ball club in baseball," Rockies manager Walt Weiss said. "It was quite a performance by him."
Chatwood (8-5), who established himself as a fixture in the rotation after coming on in late April as an injury replacement, allowed one unearned run and three hits. He walked one and struck out two in his best outing since returning earlier this month from a tender elbow that sidelined him for four weeks.
"I think it's just finding a rhythm again," Chatwood said. "You miss a month and it's not easy to get back out there in a big league game and try to pick up where you left off. It can get frustrating at times, but today I feel like I had a good rhythm, and found it again."
His Boston counterpart, John Lackey (10-13), struggled on the road again, allowing four runs and six hits in six innings. The right-hander is 1-5 away from Fenway Park since the All-Star break.
The Rockies added four runs in the bottom of the seventh to seal the win, with DJ LeMahieu and Michael Cuddyer delivering two-run singles.
Cuddyer finished 2 for 4 with a double to raise his average to an NL-best .335.
Weiss indicated that Chatwood would make one more start in Sunday's final game of the season at the Los Angeles Dodgers, and he looked forward to seeing him pitch regularly next season.
"The three guys, Jhoulys Chacin, Jorge De la Rosa and Chatty, it's nice having that in place going forward," Weiss said. "Give a lot of credit to Chatty for the improvement, the strides he's made. Pretty incredible, how far he's come."
With the AL East title wrapped up, the Red Sox are now focused on securing the best record in the league. They maintained a one-game lead over Oakland after the Athletics lost 3-0 to the Los Angeles Angels.
Manager John Farrell also is using these last few games as a way figure out his final postseason roster spots. Farrell said there are a couple still up for grabs.
David Ortiz played first base instead of Mike Napoli without the use of a designated hitter. Ortiz showed off his glove, too, snaring a scorching liner from Dickerson to end the sixth.
Chatwood pitched carefully to the dangerous Ortiz, even intentionally walking him in first with a runner on second. The ploy worked as Jarrod Saltalamacchia grounded out.
Later, Ortiz hit a fly to the deepest part of the park, but Blackmon tracked it down.
The only mistake Chatwood made wasn't on the mound but covering first base in the seventh. With two outs and Will Middlebrooks on second, Todd Helton made a diving stop on Jackie Bradley Jr.'s grounder and quickly flipped it to Chatwood, who dropped the ball before stepping on the base.
Chatwood scooped it up and threw wide to home plate and into the Red Sox dugout, allowing Middlebrooks to score. Chatwood was charged with two errors on the play and Bradley advanced to third.
But Chatwood escaped more damage when his wild pitch bounced off the wall behind home plate, allowing catcher Jordan Pacheco to quickly field the ball and flick it to Chatwood, who tagged out Bradley, keeping the score 4-1.
Saltalamacchia hit a two-run homer in the ninth after Ortiz singled.
Blackmon, the reigning NL player of the week, began the game with a homer to right on a fastball from Lackey. Cuddyer soon followed with a double and scored on Helton's single.
Helton clapped his hands after his hit as the crowd roared. The first baseman will retire at the end of the season after 17 years with the Rockies.
Before the game, Helton said he didn't "do nostalgia" and didn't want to reflect back on his career just yet. He holds virtually every hitting category in Rockies history and will play his final home game Wednesday night.
Rockies hitting coach Dante Bichette said he wants to spend more time with his family rather than return for another season. ... Rockies owner Dick Monfort is pleased with Weiss' performance and hopes the first-year manager returns. Monfort said the sides have yet to talk about a new deal. ... Rockies OF Carlos Gonzalez (sprained right middle finger) plans to take batting practice Wednesday.