SAN FRANCISCO -

Tim Lincecum had to make a decision Wednesday.

Grab for a piece of individual glory, or do what is best for the San Francisco Giants in what might turn out to be a meaningless game in May?

In the end, the two-time Cy Young Award winner looked at the blister on his right middle finger and decided to trust his bullpen.

Lincecum left a no-hitter after five innings, then watched five relievers limit the Chicago Cubs to two hits the rest of the way in the Giants' 5-0 win.

Catcher Hector Sanchez broke open a tight game with a two-run double in a three-run seventh inning, clinching the Giants' second consecutive shutout victory after the Cubs won the series opener Monday night.

"I'm disappointed in myself," Lincecum responded when asked if he wished he could have stayed in the game in pursuit of a second career no-hitter. "I didn't give myself the leash to go deeper."

In helping the Giants improve their best-in-baseball record to 34-19 while extending the Cubs' scoreless streak to 20 innings, Lincecum struggled with his control. He walked four, struck out five and was pulled in a scoreless game, having thrown 96 pitches, only 52 of which were strikes.

"There was no way he was going to go nine (innings)," Giants manager Bruce Bochy said of his call to keep Lincecum in the dugout to start the sixth. "That made the decision easier."

It was Lincecum who brought the blister, which was at the tip of his middle finger, to the club's attention. He said it first started bothering him in the third inning, and by the fifth he was starting to get a bit concerned.

"I didn't want it to get worse," he said, adding he probably could have gone only one more inning. "(It was an easy decision) because I know what our bullpen is capable of."

Lincecum got no decision in becoming the first Giants pitcher since Mike Krukow in 1983 to leave a no-hitter after pitching at least five innings.

Right-hander George Kontos (1-0) retired all four Cubs he faced to take the no-hitter one out into the seventh. Left-hander Jeremy Affeldt then battled control problems, first walking pinch hitter Justin Ruggiano and then falling behind light-hitting John Baker 1-0 before the Chicago catcher lined a single to right field.

Cubs manager Rick Renteria said he wasn't surprised to see Lincecum taken out.

"We had him on the ropes," Renteria said of his team's early chances. "We got his pitch count up to about 100 in five innings. We had some good at-bats. We actually hit some balls well."

Right-hander Jean Machi replaced Affeldt with the potential tying run on first and preserved the shutout with two ground balls. He then turned the ball over to right-hander Juan Gutierrez and left-hander Javier Lopez for the final six outs.

The Giants broke a scoreless tie with two runs in the sixth before extending the lead to 5-0 in the seventh.

Center fielder Angel Pagan ignited the initial outburst with a leadoff double off Cubs right-hander Edwin Jackson (3-5).

After a walk and a flyout, Pablo Sandoval greeted left-handed reliever James Russell with a single to center that drove in Pagan, giving the Giants third baseman at least one RBI in eight consecutive games.

Left fielder Tyler Colvin doubled off right-hander Brian Schlitter with two outs to plate right fielder Hunter Pence and make it 2-0.

A two-out error by Cubs third baseman Mike Olt opened the door for the Giants' three-run seventh against right-hander Justin Grimm. Sanchez capped the game-clinching outburst with a two-run double after the Cubs had elected to intentionally walk Sandoval.

"That's good, right?" Sanchez responded when informed he is 3-for-3 following intentional walks this season. "That's the best situation. You want to be the hero."

Jackson, who took a three-hit shutout into the sixth, struck out nine in his 5 1/3 innings. He allowed two runs, four hits and two walks.

Pagan and Sandoval had two hits apiece, combining for half of the Giants' total against four Cubs pitchers.

First baseman Anthony Rizzo had the Cubs' second hit, an eighth-inning single off Gutierrez.

Lincecum barely made it through the first inning, during which he threw 32 pitches, including 15 balls.

Walks to second baseman Emilio Bonifacio and Rizzo put two on with one out, and shortstop Starlin Castro nearly drove one in with a hard grounder between third base and shortstop. However, third baseman Sandoval snagged the shot and turned it into an out at first, with both baserunners advancing.

Right fielder Nate Schierholtz then nearly made it 2-0 with a liner down the right field line that landed inches foul. He proceeded to pop up Lincecum's 32nd pitch, ending a scoreless -- and hitless -- first inning.

"Pablo made that big play. That was critical," Lincecum said.

NOTES: Giants RHP Tim Lincecum walked 22 in his May starts, the most in the majors. His career high for a month 23, set in May 2010. ... The last Giant to drive in at least one run in eight consecutive games was 1B J.T. Snow in April 2003. ... Giants C Hector Sanchez and C/1B Buster Posey were both in the starting lineup, with San Francisco manager Bruce Bochy opting for Sanchez behind the plate. Sanchez has caught each of RHP Tim Lincecum's past five starts. The big reason: Lincecum entered Wednesday's game with a 3.79 ERA when throwing to Sanchez, 5.95 when throwing to Posey. ... Giants RHP Matt Cain reported no discomfort in his strained right hamstring after a pregame bullpen session. He remains penciled in to start Saturday in St. Louis. ... The Cubs were shut out for the seventh time this season. They were blanked in back-to-back games for the second time.