SAN FRANCISCO — Giants manager Bruce Bochy isn't sure his team has hit rock bottom just yet. He's just hoping the defending World Series champs are getting close.
At this rate, it's going to be a challenge just for San Francisco to get back to .500 let alone make a run at the postseason.
Closer Sergio Romo gave up a solo home run to former teammate Nate Schierholtz with one out in the ninth inning and the Giants were shut out for the ninth time this season in a 1-0 loss to the Chicago Cubs on Saturday night.
"We're in a tough rut now and we know it," Bochy said. "We just have to keep working and trying. We couldn't even get a cheap hit and we got what we deserve. We're being tested. I don't know why."
That the Giants wasted a second straight stellar outing by their starting pitcher made it even more harder for Bochy to stomach.
Madison Bumgarner pitched eight shutout innings for San Francisco and lowered his team-leading ERA to 2.76 but left without a decision.
That came on the heels of Friday night's 3-2 loss to the Cubs when Matt Cain allowed one run over seven innings, only to come away empty-handed when Chicago scored two unearned runs in the ninth on a San Francisco error.
The Giants committed two more errors Saturday, giving them a majors-leading 76 on the season.
Bochy said the club will skip batting practice Sunday to work on its defense. The World Series champs have lost six of seven and are a season-high 11 games under .500.
"You have to be strong to compete and smart to win," Bochy said before the game. "We have to get back to playing smarter baseball."
Dropped to sixth in the Cubs' order after batting cleanup a night earlier in the club's first game after trading Alfonso Soriano, Schierholtz worked a full count off Romo (3-6) before hitting a towering blast into the right field stands to hand Romo his second loss in as many games.
San Francisco's normally reliable closer insists the Giants haven't given up despite their struggles.
"There seems to be a lot of mishaps," Romo said. "Today was just another example where we could make some noise and it just didn't turn out our way. It does hurt. But I get an opportunity to redeem myself tomorrow."
Starlin Castro added two hits for Chicago, which is 18-13 in its last 31 games.
Pedro Strop (1-0) pitched one inning for the win despite making two mental mistakes that helped the Giants load the bases with no outs in the eighth. Strop twice made late throws on sacrifice bunt attempts but got out of it when Buster Posey and Pablo Sandoval grounded into forceouts at home and Hunter Pence struck out.
Kevin Gregg worked the ninth for his 21st save to complete the five-hitter, getting pinch-hitter Tony Abreu to ground into a 3-2-3 double play after San Francisco loaded the bases with one out.
The Cubs won their second straight in this three-game set after dropping three of four to the Giants at Wrigley Field in April. Chicago scored two unearned runs in the ninth inning to beat San Francisco 3-2 on Friday.
This one went down to the wire again.
Chicago only got one runner to second base until Schierholtz's 14th home run of the season and third on the team's current 10-game road trip. Schierholtz played with San Francisco from 2007-2012.
"My body definitely feels better," said Schierholtz, who was bothered by shoulder problems earlier in the season. "It's tough to hit big league pitching when your shoulder's not 100 percent."
That was enough to hold off the slumping Giants.
Both starters were dominant but left without a decision.
Chicago rookie Chris Rusin needed just 27 pitches to get through the third inning and didn't allow a baserunner until Pence's one-out walk in the fifth. One batter later Joaquin Arias grounded a single to center to end the no-hit bid.
Rusin also worked out of a two-on, two-out jam in the sixth and got help in the seventh when first baseman Anthony Rizzo made a leaping stab of Brandon Belt's high liner to strand Pence at third base. Pence led off the inning with a ground-rule double.
Bumgarner was equally effective until leaving for a pinch hitter in the eighth.
The Giants' most consistent starter this season and an All-Star, Bumgarner overcame a pair of errors behind him and pitched out of a two-on, two-out jam when Andres Torres made a diving catch of Schierholtz's sinking liner in the sixth. He finished with seven strikeouts and two walks.
NOTES: Giants RHP Ryan Vogelsong threw 45 pitches over 2 2-3 innings in his second rehabilitation outing after going on the disabled list with a fractured right hand. Vogelsong will accompany the big league club on a trip to the White House on Monday before joining Double-A Richmond for his next appearance. ... RHP Tim Lincecum (5-10, 4.73 ERA), who allowed 8 runs on Monday in his first start since throwing a no-hitter, pitches for the Giants in the series finale. LHP Travis Wood (6-7, 2.95) goes for Chicago and is winless in four career starts against San Francisco. ... Giants pitching coach Dave Righetti rejoined the club after having elbow surgery Wednesday.