DENVER -- The Boston Red Sox are trying to finish with the best record in the American League to gain home-field advantage in the playoffs.
The Colorado Rockies' aspirations are far less grandiose -- finish a losing season strong.
The Rockies beat the Red Sox 8-3 Monday night, hitting three solo home runs and then erupting with four runs in the seventh to blow the game open.
Colorado's Tyler Chatwood, who spent August on the disabled list with an elbow injury, won for the first time in six starts since July 26. Chatwood (8-5) allowed three hits and one unearned run in seven innings, lowering his ERA to 3.15 in 111 1/3 innings. He opened the season at Triple-A Colorado Springs after going 5-6 with a 5.43 ERA last year for the Rockies, but this season has established himself as a fixture in their rotation.
"He's got great stuff, and he's commanding it now," Rockies manager Walt Weiss said. "I think that's the big difference from a year ago."
Charlie Blackmon, Troy Tulowitzki and Corey Dickerson homered for the Rockies. DJ LeMahieu and Michael Cuddyer each had two RBIs, and Cuddyer went 2-for-4 to raise his average to .335, giving him an eight-point lead over the Atlanta Braves' Chris Johnson in the National League batting race. Johnson did not play in Atlanta's win Tuesday.
The Red Sox kept their one-game lead over the Oakland Athletics for the AL's best record. The A's lost 3-0 to the Los Angeles Angels.
Three home runs off Red Sox starter John Lackey (10-13), who pitched six innings, helped the Rockies take a 4-0 lead through four innings. Three of the four runs scored with two outs.
"Not our best night from the mound," Red Sox manager John Farrell said. "I thought John made a couple mistakes that he had to pay for. Particularly in a ballpark, you put the ball in the air, it's going to carry. The three home runs allowed were not common for him as strong as he's pitched all year. In the seventh inning, we let that game get away from us."
Lackey is 6-3 with a 2.47 ERA in 14 starts at Fenway Park, but 4-10 with a 4.48 ERA in 20 road starts.
"He's certainly comfortable in Fenway," Farrell said. "I think he takes advantage of a big right-field and center-field area. He pitches so well to his glove side of the plate, so right-handers, he's going to force them to reach for that ball on that (outer) part of the plate."
Chatwood, who pitched seven innings for the first time since July 26, got 12 outs on ground balls.
"First time we've seen him," Farrell said. "He had good stuff. To his credit, he kept the ball in the bottom part of the strike zone. Tough guy to lift, evident by the number of ground balls."
Blackmon opened the first with his sixth home run and the first leadoff homer of his career. The Rockies scored a second run in the inning when Cuddyer doubled with two outs and scored on Todd Helton's single.
Helton, who will play his final home game Wednesday night, went 2-for-4, raising his career hit total to 2,516. He entered the game tied with Buddy Bell (2,514) and is now one hit shy of tying Hall of Famer Joe Morgan (2,517) for 93rd place all-time.
Tulowitzki's two-out homer in the third gave the Rockies a 3-0 lead. It was his 25th homer of the season and third in four games. Dickerson hit his fifth homer of the season with two outs in the fourth.
Jarrod Salalamacchia hit a two-run homer in the ninth for the Red Sox, who scored a run in the seventh, courtesy of Chatwood. He made two errors on one play, dropping a toss from first baseman Helton and then throwing over the head of catcher Jordan Pacheco enabling Will Middlebrooks to score after he doubled with two out.
That was about the only thing Chatwood did wrong as he built on his last start, where he "felt really solid" but gave up four runs in six innings Thursday to St. Louis.
"I think it's just finding a rhythm again," he said. "You miss a month, it's not easy to get out there in a big league game and pick up where you left off. So it can get frustrating at times. I feel like today I had a good rhythm and found it again."
NOTES: Rockies hitting coach Dante Bichette, citing "the tug of the family," said he would not return after one season in that role. ...Red Sox CF Jacoby Ellsbury took batting practice and will be in the lineup Wednesday and play a few innings for the first time since Sept. 5. He is recovering from a compression fracture in his right foot. ... The Rockies set their rotation for the rest of the season. RHP Jhoulys Chacin will start Wednesday against Boston. RHP Collin McHugh will start Friday at Dodger Stadium, with RHP Juan Nicasio scheduled for Saturday and Chatwood set to pitch Sunday. LHP Jorge De La Rosa, who has been bothered by a thumb injury and last pitched Sept. 10, and RHP Roy Oswalt are not scheduled to start. ... Rockies C Wilin Rosario is expected to be ready to start in the weekend series at Los Angeles. A right calf strain has caused him to miss the past six games. ... With no DH in the lineup and a right-handed pitcher starting for the Rockies, left-handed-hitting David Ortiz made his fifth start of the season at first base. He went 1-for-3 with a walk. Regular 1B Mike Napoli, a right-handed hitter, did not play.