DENVER -- The Giants struggled to gain traction during their mediocre first half, but they reconvened at Coors Field with a fresh opportunity to build the momentum they need to sustain a playoff push down the stretch.

According to FanGraphs, San Francisco came out of the All-Star break with a 22.9% chance of making the playoffs, though one factor is working in its favor. The Giants have the easiest remaining schedule in the National League (.479 opponent winning percentage), with 19 of their next 23 games coming against sub-.500 teams.

Seven matchups will come against the cellar-dwelling Rockies, a team the Giants have routinely beaten up on over the last few years. But San Francisco couldn’t capitalize in the first game of this soft stretch, blowing a three-run lead en route to a deflating 7-3 loss in the club’s second-half opener on Friday night.

Left-hander Kyle Harrison allowed only one hit over five scoreless innings and departed with a 3-0 lead, but the Giants’ bullpen couldn’t hold it from there. Brenton Doyle cranked a two-run shot off Randy Rodríguez, cutting the deficit to one in the sixth. Colorado tied the game after Jake Cave reached on a leadoff double and scored on a two-out throwing error by third baseman Matt Chapman in the seventh.

Cave came back to deliver the knockout blow in the eighth, crushing a go-ahead, three-run blast off Tyler Rogers that highlighted a four-run rally for the Rockies. The defeat dropped the Giants four games under .500 (47-51) with 11 days to go until the July 30 Trade Deadline.

“Every loss stings, but when you have a lead when [Harrison] comes out, yeah, it hurts a little bit,” manager Bob Melvin said. “Very uncharacteristic of them, giving up some runs. Give them credit. They put together some good at-bats and scored some runs off some good relievers.”

It certainly wasn’t how the Giants hoped to start the second half, especially after receiving an impressive performance from Harrison, who hasn’t allowed a run over his last 12 innings at the notoriously hitter-friendly Coors Field. Harrison walked four and struck out six in the 93-pitch effort, leaning almost exclusively on his fastball and slurve breaking ball to stymie Colorado’s lineup.

“I think, for me, it was really the same plan and approach,” said Harrison, who tossed a career-high seven scoreless innings in his last start at Coors on May 7. “Something I haven’t been doing was the first-pitch strike, so we really wanted to stress that today. Came out doing that. I feel like I had a lot of outings [at Triple-A] last year in high-altitude places like Reno and Vegas, so I kind of had a feeling of how my ball was going to move and where to land it. Not land it in that honey hole in to righties. Just mixing it up.”

The Giants got on the board early thanks to Thairo Estrada’s two-run triple in the second and Patrick Bailey’s RBI groundout in the third, but a couple of bad breaks ultimately helped swing the game in favor of the Rockies. San Francisco had a chance to add on after Chapman walked and Estrada reached on a hit-by-pitch in the fourth, but Brett Wisely’s would-be double down the right-field line, deflected off umpire Chris Conroy and ricocheted directly into first baseman Michael Toglia’s glove.

Toglia quickly ran to first base and slid into the bag for an out, robbing Wisely of an extra-base hit that likely would have stretched the Giants’ lead to 5-0.

“That’s just unlucky,” Wisely said. “If something like that were going to happen, it’d probably be to me. It is what it is. It’s baseball. Weird stuff happens all the time. Just got the bad end of the stick there.”

The Rockies had another call go their way in the sixth when home-plate umpire Brian O’Nora awarded Elias Díaz first base after he appeared to be struck by a pitch from Rodríguez. The Giants tried challenging what Melvin felt was a “phantom hit-by-pitch,” but the ruling was upheld following a replay review, which helped set up Doyle’s two-run shot to left-center field.

“It adds up,” Melvin said. “Very frustrating, but we didn’t add on, and we gave up too many runs at the end.”