Rosario wasn't alone. A baserunning mistake by another rookie, Charlie Blackmon, cost the Rockies a possible run in the sixth, and Blackmon's ill-advised dive in the ninth allowed the Giants' Angel Pagan to notch his 14th triple of the season and opened the door for a two-run eighth. The Rockies also failed to score after loading the bases with one out in the seventh.
After playing many lopsided games because of bad pitching in the first half of the season, recent games have featured some signs of progress but just as many glaring areas that need improvement. Rosario's story is that of the Rockies, who are smiling and straining their way through a season that they hope leads to something glorious.
The Rockies trailed, 4-0, when Rosario clubbed a Santiago Casilla pitch into the left-center bleachers. The deficit might have been just three runs had Rosario kept a Josh Roenicke pitch in front of him with Marco Scutaro at third in the seventh. It was another lesson.
"It's tough being a catcher in the Major Leagues when it's your first time here and you play a lot," Rosario said. "I like the opportunity I have. The game here is quicker. Every ball I miss, the next day I work hard. I don't want to miss again.
"I work hard on my defense, and I enjoy when I hit -- that's my home right now. When I've got a bat, I feel happy. When I go behind the plate, that's the time for work."
The Rockies couldn't support a solid effort from starter Jeff Francis (5-6), who gave up two runs on six hits in five innings, because they couldn't score in 6 1/3 innings against Giants starter Tim Lincecum (10-14).
"We battled," Rockies manager Jim Tracy said. "They just pecked at us."
For Francis, it was an improvement over his last start against the Giants, when he gave up five first-inning runs, left after three innings and absorbed the losing decision at Coors Field last Wednesday.
"I was ahead in the count quite a bit and gave myself a chance to stay on the corners a little more, be a little finer," Francis said.
Lincecum struck out six and gave up five hits and has shaken off a poor start to win six of his last 10 starts. The Rockies had a chance in the sixth.
Giants shortstop Brandon Crawford plunked Dexter Fowler in the helmet while trying to relay to first on a double-play attempt. But the hitter, Blackmon, ran past the bag and never noticed that the ball had caromed behind home plate. Blackmon later tried to steal second and was thrown out. A Jordan Pacheco hit later in the inning, which should have driven in a run, didn't.
Lincecum left the game in a precarious spot, with the bases loaded and one out in the seventh. However, Giants reliever Jeremy Affeldt forced veteran pinch-hitter Jason Giambi to hit into a double play on the first pitch.
Given the history, that at-bat does not go down as one of the Rockies' fundamental failings, even if it was quick and unsuccessful. Giambi entered 6-for-14 against Affeldt in previous meetings, and his plan was based on those previous at-bats.
"I don't know what else could have gone wrong in that inning, really," Giants manager Bruce Bochy said. "Catcher's interference [that let Tyler Colvin reach first], a ball that's right down the line there [a Chris Nelson single, although replays showed the ball bounced foul], and Buster [Posey at first base] made a good play but he couldn't quite get a handle on it [for a DJ LeMahieu single] to put Timmy in a tough jam.
"But Jeremy picked us up. We got that ground ball we were looking for."