Germano responded by driving in a run and giving up none to help the Padres beat the Diamondbacks 4-0.
"I was very proud of him, going against an All-Star on the road, a team that had a lot of momentum, and he held them down," manager Bud Black said. "A great job."
Milton Bradley drove in two runs and Brian Giles had three hits for San Diego, which remained a game back of Los Angeles in the NL West.
The Padres rebounded from a deflating 5-4 loss on Saturday night, when they blew a 4-0 fifth-inning lead with ace Chris Young on the mound.
Germano (6-3) gave up four hits in 6 1/3 innings, walking three and striking out four. Germano, who is hitting .333 (5-for-15), also singled home a run in the sixth, when the Padres chased Webb (8-7).
Germano had slumped after winning his first five decisions. In his last two starts, he yielded 12 runs and 18 hits in 10 2/3 innings. But the All-Star break clearly did him good.
"It was huge just to get my confidence back up," Germano said. "Those last couple of outings kind of linger. You don't want to think about them, but they are in the back of your mind."
Heath Bell, Scott Linebrink and Doug Brocail completed San Diego's 13th shutout, most in the majors.
The Padres are hitting .243 as a team, worst in the NL. But they connected against Webb, who allowed three earned runs and a season-high 11 hits in 5 2/3 innings. He walked two and struck out 10.
"If you start swinging at stuff around your knees, he's extremely tough on you," Giles said. "I think the good thing is we got him up in the zone. We made him really work out there."
San Diego took a 1-0 lead in the third when Giles singled, stole second and scored on a single by Bradley.
With two outs in the fifth, Adrian Gonzalez doubled and went to third on left fielder Scott Hairston's error. Mike Cameron singled through the left side of the infield to make it 2-0.
In the sixth, Russell Branyan tripled to right-center. With two outs, Germano drove a 1-2 fastball to right field to make it 3-0. Bradley added an RBI single later in the inning.
Webb said he didn't feel he had been hit very hard.
"Overall, I thought I had pretty good stuff," Webb said. "There was a lot of broken-bat hits. If I didn't strike them out, I wasn't getting them out."
Meanwhile, Germano was cruising. He allowed only one hit through five innings -- a sharp single to left by Chris Snyder, a .214 hitter.
"The guy just pitched very well against us, had us off balance all day," Arizona manager Bob Melvin said.
In the sixth, Chris Young and Eric Byrnes singled to open the inning. But Germano got Stephen Drew on a fly to left and struck out Orlando Hudson and Mark Reynolds to end the threat.
"In every game, it comes down to a key at-bat, a few critical pitches," Black said. "In this case, when he struck out Reynolds, that was a key at-bat."
Black pulled Germano in the seventh after he gave up a double to Conor Jackson and walked Chad Tracy one out later. Bell got Snyder to ground into an inning-ending double play.
Linebrink and Brocail followed with a scoreless inning apiece.
On Saturday night, Bell gave up five hits in a third of an inning and Linebrink took the loss as the Padres' stalwart bullpen blew a 4-1 seventh-inning lead. Black didn't hesitate to go back to both of them one day later.
"What we saw last night is an extremely rare occurrence," Black said. "I have without any hesitation a great deal of confidence in our bullpen."
Giles had two stolen bases in his first 53 games. He had two in the first three innings Sunday against Webb and Snyder. Padres SS Khalil Greene also doubled his steal total -- to two. ... Last year, Webb didn't lose his seventh game until Sept. 21 on his way to the NL Cy Young Award.