Weakened by the aftereffects of bronchitis, Tim Lincecum allowed four runs and seven hits in 3 2/3 innings while his teammates went scoreless for five innings against a legitimate starting pitcher for the second day in a row.

Also for the second consecutive game, the Giants' substitutes surged late. Nick Noonan, a leading second-base prospect, lined a grand slam to cap a five-run ninth-inning uprising that gave San Francisco an 8-6 victory over the Chicago Cubs at HoHoKam Park.

The Giants' comeback from a 5-0 deficit included another home run from Jesus Guzman, the non-roster invitee who's hitting .421 with a 1.000 slugging percentage. Asked if underdogs such as Guzman can hit their way onto the Opening Day roster, manager Bruce Bochy smiled and said, "It's a great way to get there."

Entertaining as Noonan and Guzman were, the afternoon's key figure from the Giants' perspective was Lincecum, the National League's reigning Cy Young Award winner. Not only did Lincecum's illness delay his pitching assignment by two days, but it also denied him the chance to throw in the bullpen between starts, which upset his routine.

"My energy was not all the way there," Lincecum said, explaining that his subpar health also disrupted his pitching rhythm -- which is the source of his usual excellence. "I just need to get back to 100 percent and get my body feeling good so everything's working right and I get good rhythm out there."

Lincecum entered the game unscored upon in 9 1/3 exhibition innings, having allowed just two hits. Any notion that Lincecum might extend his streak vanished with his first pitch, which Chicago's Alfonso Soriano clobbered for a home run.

"That kind of woke me up a little bit, I guess," Lincecum said. It also launched Chicago's three-run first inning in which the first five Cubs batters reached base safely.

Catcher Bengie Molina, not Lincecum, accounted for two of the first five outs the Giants recorded by throwing out Cubs attempting to steal.

Lincecum rated his performance as "pretty subpar" but tried to salvage value from it. Many pitchers actually welcome Spring Training games in which opponents hit them hard and they cope with runners on base, since that conditions them to face similar jams in the regular season. Lincecum acknowledged this by saying, "You have to think more out there. it's not going to be 1-2-3 every outing. You actually have to work yourself out of situations."

Lincecum's six strikeouts indicated that he wasn't entirely bereft of stuff.

"I felt like at times my changeup was good, at times I threw good curveballs and at times I threw good fastballs," he said. "It was a matter of finding it consistently enough."

After mustering one hit Tuesday off Milwaukee's Jeff Suppan, whom they might face in the April 7 season opener at AT&T Park, the Giants collected four hits off Chicago's Ryan Dempster but moved only two runners as far as second base. Both days, Bochy filled his lineup with mostly projected regulars.

Right fielder Randy Winn, who's batting .150, isn't overly worried about himself or his teammates.

"We still have quite a ways to the opening bell," said Winn, who singled sharply off Dempster in the first inning. "Some guys are swinging the bat better than others. Some guys are working on things. Some guys are hitting the ball hard and making outs. When you get a little bit closer to Opening Day, you hope that you're firing on all cylinders. But at this point, I still think it's a little bit early to be concerned."

Winn and the other regulars were long gone when the Giants completed their rally. Eugenio Velez, proving his sore right ankle felt fine, tripled to right-center field off Jose Ascanio with one out in the ninth and the Giants trailing, 5-3. Juan Uribe lashed an RBI single before Guzman popped out. Andres Torres, another intriguing non-roster player who's batting .457, singled, and Buster Posey was hit by a pitch to load the bases. Up came Noonan, the 32nd overall selection in the 2007 First-Year Player Draft, who pummeled a 2-1 pitch over the right-field barrier.

This was the third time the Giants summoned the 19-year-old Noonan from Minor League camp to be used as a late-inning replacement. Before the ninth began, he calculated that he'd be the inning's seventh batter if it lasted that long.

"I thought maybe if we got a little rally going I'd have a chance to come up in a big spot," Noonan said.