DENVER -- Andrew Toles was out of baseball last year.

When he joined the Los Angeles Dodgers' organization this year, he began at the high Class A level.

Rancho Cucamonga in the California League is far removed from the major league radar. So far that after Toles hit his first career grand slam with two outs in the ninth inning Wednesday to highlight a five-run inning and lift the Dodgers to a stunning 10-8 comeback win over the Colorado Rockies, Los Angeles manager Dave Roberts admitted, "To say when spring training started if I'd ever heard of the name Andrew Toles, I'd be lying."

Toles, 24, made his major league debut July 9 and began his second stint with the Dodgers on Aug. 21. He is hitting .397 (23-for-58) in 25 games for Los Angeles and is impressing Roberts with more than his ability.

"He's just so calm and cool," Roberts said, "The little bit of the naivete and not knowing how good some of these pitchers are or the ballparks or what's at stake, it's just like a young player just going out there and playing baseball in his backyard."

Stephen Cardullo hit his first career grand slam in the first inning when the Rockies took advantage of spot starter Bud Norris' wildness and built a 5-1 lead.

Cardullo, whose pinch-hit homer in the first game Wednesday was the first long ball of his career, is the first player to homer in both games of a doubleheader on his birthday since Hall of Famer Tony Perez on May 14, 1972. He joined Angel Pagan (2006) as the only players to hit their first two major league homers on their birthday.

With the Dodgers trailing 6-2 midgame and staring at getting swept in both the doubleheader and three-game series, Roberts was pondering some necessary rally-the-troops business.

"I think that I had my motivation speech ready maybe after the fifth today," Roberts said.

No such oratory was necessary. The Dodgers scored three runs in the eighth and five in the ninth. It was the fourth time in franchise history and second time since the move to Los Angeles that the Dodgers overcame a deficit of six or more runs in the eighth inning or later. The previous occurrence was in May 1994.

The Rockies tied their record for the biggest blown lead in the eighth and ninth innings in franchise history.

Colorado won the first game of the doubleheader 7-0 as Tyler Anderson threw 6 1/3 innings. That victory assured the Rockies of winning their fifth consecutive series -- all in August -- against teams currently in first place in the National League. But that was small solace after such a deflating loss.

"This one hurts," said Nolan Arenado, whose 36th homer, a two-run shot in the seventh, gave the Rockies an 8-2 lead and extended his franchise record for RBIs in August to 36. "It kind of puts a little damper on the series win. I think we're all happy because we won the series, but we're in a position where we can't give up games. When you have a chance to sweep, you've got to be able to sweep."

Colorado reliever Matt Carasiti, who has been scored upon in eight of his 10 career outings, yielded three runs in the eighth. He gave up back-to-back doubles with one out to Adrian Gonzalez and Yasmani Grandal, followed by a walk. Rockies manager Walt Weiss then turned to Carlos Estevez.

Joc Pederson grounded Estevez's first pitch into right field for a run-scoring single. Toles lined a 2-0 fastball for a single, loading the bases for pinch hitter Howie Kendrick, who hit a sacrifice fly to right to make it 8-5.

Ottavino (0-1) walked Corey Seager on five pitches to open the ninth. He struck out Justin Turner and got Gonzalez to line to shortstop before Grandal and Josh Reddick singled to make it 8-6 with his first RBI since joining the Dodgers on Aug. 2.

Pederson walked to load the bases. The left-handed-hitting Toles then cleared them, driving Ottavino's 0-1 fastball 382 feet into the left field stands.

"You're going to blow games. You're going to lose games," Ottavino said. "You're going to pitch bad from time to time. I should never give up five runs in an inning. I should never walk two guys in an inning."

Toles, whose run-scoring double in the second broke Los Angeles' 0-for-20 streak with runners in scoring position, said, "I saw a slider first pitch, it was a little up. The next pitch was a fastball, and I put a good swing on it."

Luis Avilan (1-0), who was added to the Dodgers' roster as the 26th player for the second game, retired the side in order in the eighth, and Kenley Jansen gave up a two-out single but struck out the side in the ninth, finalizing both his 40th save and the Rockies' agony.

"That one (stunk)," Weiss said. "No doubt about it. We won the series, but it doesn't feel like it because we had that game in hand. We've got an off day tomorrow, and we've got a little extra time to recover from this one. We've been playing real well, and it's a shame we lost this one."

The comeback means the first-place Dodgers start September with a 1 1/2-game lead over the second-place San Francisco Giants in the National League West.

NOTES: Dodgers RHP Bud Norris started the second game in place of LHP Rich Hill. The Dodgers didn't want to risk Hill, who threw 41 pitches warming up for Tuesday's game that was postponed, having his left middle finger become inflamed. Hill is just one start removed from missing a month due to blisters. ... Dodgers 2B Chase Utley's leadoff homer was the fourth of his career and third this season. ... Rockies RHP Christian Bergman and Dodgers LHP Luis Avilan were recalled from Triple-A and added to the teams' roster as the 26th players for the second game of the doubleheader. Bergman was optioned after the game.