ATLANTA -- Rockies third baseman Nolan Arenado couldn't believe he booted a routine grounder that could've helped the Colorado Rockies hold a four-run lead in the third inning.
"I needed to make that play," he said. "That was a big error."
Scott Downs (1-0) earned the win after being acquired in a trade with the Los Angeles Angels earlier in the day and arriving at Turner Field not long before the first pitch. The left-hander allowed one hit and struck out one in 1 1-3 innings.
Escalona (1-4) allowed one hit, one run and one walk in 12 pitches.
Downs escaped a bases-loaded jam in the ninth by making just one pitch, a liner he caught on the mound from Todd Helton.
Gonzalez went 5 for 5 with two RBIs after missing the last three games with a sprained middle right finger. He drove in the tying run in the ninth off Jordan Walden.
"It was tough to lose a game like this," Gonzalez said. "The way we played tonight we probably should have won, but they got the big hit."
Atlanta's offence bailed out starting pitcher Brandon Beachy, who made his first start in 13 months after undergoing elbow ligament replacement surgery.
Chris Johnson, who leads the NL with a .339 batting average, and Uggla each had two RBIs to help the Braves erase a 5-0 hole with six runs in the third inning, then rally from a two-run deficit in the fifth to make it 8-7.
Beachy gave up eight hits, seven runs and one walk with five strikeouts in 3 2-3 innings. He made 84 pitches, 58 for strikes.
With Braves closer Craig Kimbrel unavailable after earning saves in all three games against St. Louis last weekend, Walden gave up two hits, walked two in two-thirds of an inning and left with the bases loaded.
Rockies starter Jorge De La Rosa gave up 10 hits and eight runs -- five earned -- with two walks and three strikeouts in five innings.
Arenado's error in the third ruined a chance for an inning-ending double play.
After Jason Heyward's one-out RBI single made it 5-1, Arenado let Evan Gattis' bases-loaded grounder bounce off the heel of his glove, allowing Heyward to score and keep the bases loaded.
Johnson followed with a two-run double before Uggla had an RBI groundout and Simmons' RBI double gave the Braves a 6-5 lead.
"I think I pulled my head from the ball," Arenado said. "If I would have just stayed down, I think I would have had it. I should have gone home. My instincts should have just kept going through the ball and go toward home."
All of Gonzalez's five hits were singles, raising his average nine points to .306. Gonzalez matched his career high for hits, which he last accomplished in a 9-4 victory at the Chicago Cubs on May 14.
The Rockies took a 1-0 lead in the first on Gonzalez's RBI single and went up 2-0 in the second on Wilin Rosario's 15th homer.
In the third, Colorado led 4-0 on a two-run triple by Michael Cuddyer, who scored to make it 5-0 on Helton's sacrifice fly.
"We played a tough game," Rockies manager Walt Weiss said. "We got up early. You've got to put those games away. We didn't put it away."
Notes: Rockies INF Charlie Culberson, recalled from Triple-A Colorado Springs earlier in the day, grounded out as a pinch hitter in the 10th. Culberson had several family members and friends who drove south from Rome, Ga., hoping to see him play. ... Walden blew his second straight save opportunity and first since April 26, 2012, when he pitched for the Los Angeles Angels at Tampa Bay. ... Atlanta improved to 8-4 in extra innings. Colorado dropped to 5-8. ... De La Rosa had gone 3-1 with a 1.96 ERA in his last seven starts. He left for a pinch-hitter in the sixth. ... Beachy last pitched on June 16, 2012, against Baltimore. He missed 105 games recovering from a torn right elbow ligament and was tied for the major league lead with a 2.00 ERA when he was injured.