"It just got out of hand," Kennedy said. "I felt like I didn't miss by a whole lot but those homers really didn't help. It's really frustrating when you try to go out and put a good start together to give your team a chance to win."
Based on the right-hander's results since the All-Star break, the bases on balls and homers he allowed came as little surprise. In nine starts after the halfway mark, Kennedy has handed out 19 walks and served up 14 long balls. He gave up just 19 total in all of last season.
"To be honest, you can't talk about last year," Kennedy said. "But it's not that much more, a lot of times they come in bunches. It's part of this game and it's a part of pitching."
Saturday marked Kennedy's first career loss against the Padres. The 27-year-old entered his start with a 6-0 record against the club and a 2.34 ERA over 57 2/3 innings.
"He threw the ball good at first, the home runs hurt him," D-backs manager Kirk Gibson said. "They were being very productive with their at-bats."
To make the defeat sting even more, the D-backs collected as many hits as the Padres, seven, but batted 0-for-6 with runners in scoring position.
One bright spot for Arizona came off the bat of Justin Upton, who drove a ball into deep right-center field that ricocheted off the wall far enough for the outfielder to touch all the bases for his first career inside-the-park homer.
Upton, who celebrated his 25th birthday Saturday, became the first player to hit such a home run on his birthday since Lou Brock on June 18, 1976, according to Elias.
"I knew it was at least a double when I hit, then I knew I had a chance to score and turned it on," Upton said. "Luckily I got there."
Aaron Hill contributed the only other run of the game for the D-backs, hitting his 19th homer of the season in the eighth.
Chase Headley and former D-back Carlos Quentin each hit long balls to leave the score tied at 2 after the fourth.
An inning later, Kennedy served up his third hit and third solo homer of the night, this time to Yonder Alonso, giving the Padres a 3-2 lead.
The D-backs looked poised to even the score in their half of the fifth but with one out and Miguel Montero on third base, John McDonald grounded sharply to third and the Padres eventually caught Montero in a rundown and tagged McDonald out at second to end the threat.
"We had a couple opportunities to get a couple runs, but we didn't do that," Gibson said. "They out-executed us in every aspect of the game, that was it."
Kennedy's command got away from him in the sixth and the Padres took advantage. After putting three runners on base without giving up a hit, Kennedy walked a run home then allowed a two-run single to Alonso to break the game wide open, 6-2.
"They're putting really good at-bats together, they are hitting the ball well," Kennedy said. "You can see they are taking a lot pitches and fouling off the good ones to get to deeper counts. They've done a really good job of that."
Meanwhile, Padres starter Clayton Richard cruised through his eight innings of work, allowing just the three runs and earning his first road win since defeating the D-backs on July 2.
"Defensively we were terrific, they really kept me in the game," Richard said. "A couple of plays that Chase [Headley] made, I really don't think I would have lasted that long if he didn't make those plays. I was fortunate tonight."
The Padres added three runs in the eighth to cap off their night and extend their franchise-best winning streak at Chase Field.