DENVER — Dave Roberts wanted to avoid using two of his top three relievers on Wednesday night after de facto closer Evan Phillips pitched in the previous three games and setup man Brusdar Graterol pitched in three of four games.

So with a two-run lead in the sixth inning and dark storm clouds moving in over Coors Field, the Dodgers manager had little choice but to turn to a pair of lower-leverage arms in hopes of bridging the gap between starter Michael Grove and back-end relievers Yency Almonte and Caleb Ferguson.

The bridge buckled under left-hander Victor Gonzalez and collapsed under righthander Nick Robertson, who combined to give up five runs and four hits in the bottom of the sixth inning of an eventual 9-8 loss to the Colorado Rockies.

The Dodgers had scored six runs in the fourth inning, a rally capped by Mookie Betts’ three-run homer, to take a 6-4 lead, and Grove, who allowed four runs and eight hits in five innings of a spot start, retired the side in order in the fifth.

Gonzalez struck out Nolan Jones on three pitches to open the bottom of the sixth before Randal Grichuk rifled a single to center field and took third on pinch-hitter Jorge Alfaro’s double to right-center. Gonzalez hit No. 9 batter Brenton Doyle with a pitch to load the bases and was replaced by Robertson.

Jurickson Profar walked to force in a run to cut the Dodgers’ lead to 6-5. Ezequiel Tovar followed with a three-run double that one-hopped the wall in right-center to give the Rockies an 8-6 lead, a ball that Dodgers center fielder James Outman got a late jump on but probably wouldn’t have caught anyway. Ryan McMahon struck out, but Elias Diaz lined an RBI single to center for a 9-6 lead.

The Dodgers rallied for two runs in the eighth to trim the deficit to 9-8, Jason Heyward and David Peralta sparking the rally with singles, Yonny Hernandez hitting a sacrifice fly to left, Betts walking and Freddie Freeman hitting an RBI single to center.

Will Smith walked to load the bases with two outs, but J.D. Martinez struck out swinging at a 2-and-2 sweeper from right-hander Justin Lawrence to end the inning. Lawrence retired the side in order with two strikeouts in the ninth to close out the game.

The Rockies held a 4-0 lead through three innings on the strength of Harold Castro’s RBI single in the second and a three-run third that featured a C.J. Cron bloop RBI single that left his bat at 68 mph and traveled 236 feet to left-center field and Grichuk’s two-run bloop single that left his bat at 65.6 mph and traveled 226 feet to left-center.

The Dodgers countered with a six-spot in the top of the fourth, a rally that started with walks to Smith and Miguel Vargas and a Miguel Rojas bloop single to center field that loaded the bases with one out.

Outman flied to shallow center, the runners holding, but Jonny DeLuca took a fullcount, down-and-in fastball from Rockies left-hander Kyle Freeland for ball four to drive in a run.

Hernandez followed with a broken-bat, two-run single to center to pull the Dodgers to within 4-3, and Betts drove a first-pitch curve 404 feet to left field for his 20th homer of the season, a three-run shot that gave the Dodgers a 6-4 lead.