Cain seemed like the best candidate of any to keep the scoreless streak alive, entering the game with a 4-0 record and 1.25 ERA in June. But Cain was hardly dominant from the first pitch on, tying season highs by allowing five runs on 11 hits as he lost for the first time since May 1.
"They're an aggressive team and you want to keep them off balance," Cain said. "I was getting them swinging but wasn't making quality pitches."
The Reds got two more runs in the first inning to take a 3-0 lead. A Drew Stubbs walk was followed by a Joey Votto double, and Jay Bruce brought them both home with a double.
"It's huge," Bruce said of getting runs off Cain early. "Zack set the tone. You have to take anything you can get off of Matt. He's one of the game's best. You've seen what he can do. You see what he does pretty much every time out with the numbers he puts up every year. He made a few mistakes tonight that we took advantage of."
After settling down to hold the Reds to four singles through the next four innings, Cain allowed a home run to Leake in the sixth inning and left after giving up an RBI double to Bruce with one out in the seventh.
"Matty was a little off today, a little out of sync," Bochy said. "He was having trouble getting the ball where he wanted. It's going to happen. He's been so consistent, and he was off today, but there he was pitching in the seventh. He battled out there."
And after having been the beneficiaries of stellar pitching in the last four games, the Giants' bats fell mostly silent against Leake. The Giants managed nine hits on the night, but went 0-for-8 with runners in scoring position and left seven runners on base. Pablo Sandoval's one-out homer in the ninth prevented the shutout.
"We had a couple chances to get back in the game. We just couldn't get a timely hit there," Bochy said. "We need to put this one behind us."
The Giants looked to threaten in the fourth with runners on first and second and one out. The Reds tried to turn a double play on Brandon Belt's grounder up the middle, but Sandoval slid hard into second base, swiping Cozart's leg to make him twist and fall to break up the double play. Reds manager Dusty Baker trotted out to argue, and the umpires signaled interference on Sandoval soon after to end the inning.
"They got it right," Bochy said. "The slide was fine. You're trying to break up the double play there, and he slide early and past the bag. But the thing is he grabbed the shortstop, which you can't do."
Leake had previously gone nine innings in a 13-inning win against the Cubs last September, but went the distance for the first time Friday night.
"I'm not huge on complete games but it was nice to get one finally," Leake said. "It couldn't happen without the defense we had today and the early start we got in the first inning."
Cain's outing came after Barry Zito, Ryan Vogelsong and Tim Lincecum all had seven-inning scoreless starts in a three-game sweep of the Dodgers and Madison Bumgarner pitched a one-hit complete game against the Reds on Thursday.
"It was a great run; I'm just sad I couldn't keep it going. I wanted to follow that up, and I didn't do that. You expect yourself to go out there and throw well, and it didn't work."