Helton's sixth homer of the season, to straightaway center field off Kyle Lohse (2-7), was all Francis needed. Francis (5-4) retired the first 12 hitters and held the Reds to five hits, with six strikeouts and one walk, in seven innings.
The Rockies didn't get much more. Matt Holliday drove in a run with a third-inning single, which extended his hit streak to 11 games, and an unearned run scored in the eighth.
Still, the Rockies' 4-for-33 (.133) performance with runners in scoring position during the losing streak never came into play Saturday, thanks to Francis, who is 4-0 with a 1.64 ERA in his last six starts.
"Ah, man, he's throwing the ball well," said Helton, who noted after Friday night's 4-2 loss to the Reds that the Rockies' hitters had been pressing. "You've got a feeling that things are going to turn out OK."
The Rockies could have had that feeling by looking at the stat sheet and seeing that the Reds are worst in the National League against left-handed starting pitchers. Francis sent Cincinnati to 7-17 vs. lefty starters with an effectiveness that would have worked against any club.
Francis also is becoming dependable.
His road victory against the Diamondbacks on May 23 began a seven-game win streak for the Rockies. He beat the Cardinals on Monday to open the homestand -- and the Rockies are not even that comfortable at Coors, as evidenced by their 13-16 record.
Saturday, he stopped a losing streak.
"I'm throwing well," Francis said. "My teammates kind of expect me to throw well, and there's an energy when your team's depending on you."
Edwin Encarnacion ended Francis' shutout bid in the seventh with a one-out, RBI double. But Francis worked David Ross into a groundout and Juan Castro into a fly ball. Francis finished with 96 pitches, 65 strikes.
"His command is just top-shelf," Rockies manager Clint Hurdle said. "His pitch efficiency has been very, very good. He's in command of all three pitches."
Reliever Manny Corpas pitched a perfect eighth, finishing it by handing Ken Griffey Jr. his third strikeout. Closer Brian Fuentes earned his 16th save and extended his string of successful opportunities to 11 with a scoreless ninth.
Rockies rookie shortstop Troy Tulowitzki left after five innings with right groin tightness. Tulowitzki, who has played all but six of the Rockies' 305 innings while starting 34 straight games, fought to stay in and hopes to play Sunday.