Cahill, who was acquired from the A's in a trade that involved one of Arizona's top pitching prospects, Jarrod Parker, walked three and struck out five.
"He has a good sinker, and that was evident," Padres manager Bud Black said. "We couldn't really dig the ball out. He changed speeds more than I thought he did with the A's. He kept us off-balance."
It was the first win for Cahill (3-5) since he beat the Nationals on May 1 and it was just the second complete game by an Arizona hurler this year. Joe Saunders had the other on April 27 against the Marlins.
Cahill was not sure what to make of what Gibson had told him the night before.
"I was kind of caught off guard," Cahill said. "He kind of scared me a little bit. I felt like our pitchers have been throwing the ball really good, especially this series. He just wanted to see how I responded. It was one of those things, he just got me so off guard. I was like, 'Huh?'"
Cahill had his sinker working and it helped him get four double plays and it also kept his pitch count manageable as he threw just 109.
It was the latest in a string of good outings from a starting rotation that has for the most part underachieved.
"We're on a good streak this time through the rotation," Gibson said. "It's what we've been looking for. We've been wearing our bullpen out and guys weren't going as deep as they were capable of. Now they're all throwing the ball well this time through, so we hope that continues. It's a good trend."
Whereas hitters often say that hitting is contagious -- once one hitter heats up, others tend to follow -- the same can be said of starting pitchers.
"The other starting pitchers use it like a competition almost," Cahill said. "Kind of build off each other.
I think everybody has been throwing the ball a lot better, pounding the zone and I think that kind of carries over."
Speaking of carrying, the ball was doing just that off the Arizona bats Sunday.
In a ballpark that is known to be tough on hitters, the D-backs smacked three homers, two of which went to the opposite field and the other to straightaway center.
"I can't remember the last time we had a two-run homer and we had two tonight," Gibson said.
First baseman Paul Goldschmidt continued his hot hitting as he got the D-backs on the board in the second with a solo homer to right off Padres starter Eric Stults (1-2).
"I hit the ball good," Goldschmidt said. "He threw a couple changeups early on, good pitches down so I had seen it a couple of times and that one was up and caught more of the plate than the previous ones."
The Padres threatened to tie things up in the fifth when Logan Forsythe led off with a triple, but a missed suicide-squeeze attempt allowed the D-backs to get out of the inning without any damage.
"That was big when they had that guy on third and missed a squeeze and that kept us in the lead and kept the momentum going," Goldschmidt said.
The D-backs came right back with three runs in the sixth, two of which came on Miguel Montero's homer to center.
One inning later, Gerardo Parra smacked a two-run homer of his own to left to give Arizona an added cushion.
Prior to Parra's at-bat in the seventh, an elderly woman sitting behind the on-deck circle yelled some encouragement to him. Parra walked up to her and asked her to touch his bat and promised to give her the bat if he got a hit.
After he circled the bases on the homer, Parra signaled to the bat boy to give him his bat back and he walked over and handed it to the woman.