SAN DIEGO -- There are going to be some growing pains for the D-backs these last couple of months of the season as their roster gets younger both in age and experience.

That was on display in the eighth inning on Saturday night as the D-backs committed a trio of mistakes and the Padres capitalized for four runs and a 6-2 win in front of a sold-out crowd at Petco Park.

• Box score

Here's a look at things to know about the game:

It was a nice outing by Widener
Taylor Widener, who had allowed five runs in each of his last three starts, battled his way through five good innings, allowing just a pair of runs -- solo homers to Manny Machado and Eric Hosmer.

There were two main adjustments Widener made to get himself headed back in the right direction.

First, he ironed out some mechanical issues, the first of which involved staying back over the rubber better. The second one came into play when he had men on base.

"I was squatting a little too much whenever I was getting in the stretch," Widener said. "And it was kind of causing me to pop up. So I tried to clean that up a little bit."

Widener spent two stints on the injured list this year with groin muscle issues, so he did not feel he was as strong as he had been.

"I started over in the weight room," he said. "Just kind of start over at square one, going back to a little bit lighter weight and just trying to rebuild all the strength that I feel like I lost."

Widener's big moment
The biggest test for Widener came in the fourth when he loaded the bases with no one out and catcher Victor Caratini coming to the plate. Getting Caratini was crucial, because Widener knew he had the pitcher, Yu Darvish, on deck.

Widener got Caratini to pop out to short and Darvish to hit into a double play.

"It was just him believing his stuff and getting after it, getting big outs and getting the team back in the dugout with the score tied," D-backs manager Torey Lovullo said. "That's what we look for from our starting pitchers -- the damage control, not giving up those scratch runs and making pitches when your back is against the wall. Taylor did all that today."

Signals got crossed
With two outs and the score tied at 2 in the eighth, Josh VanMeter singled and Lovullo sent up the right-handed-hitting Carson Kelly to pinch-hit against left-hander Drew Pomeranz. It was, Lovullo said, one of the most favorable matchups for the D-backs the entire night.

Kelly never got to hit, though, as VanMeter attempted to steal second, Pomeranz threw to first rather than going home and VanMeter was out to end the inning.

"There was a mixup in communication between me and the coaches," Lovullo said. "Ultimately, it's my fault. I've got to put the red light on. There's a lot of nonverbal communication. There's a process that we follow. I think we were just trying to do a little too much in that situation and got clipped. It wasn't a great baseball play. I'll be the first to admit that. We need to be a little better, and that's on me."

Stolen base the other way
In the bottom of the eighth, Adam Frazier led off with a single and stole second easily against Brett deGeus. Frazier got such a great jump, in fact, the D-backs did not even attempt a throw.

It was an example of a pitcher getting a little too predictable on the mound.

"Frazier picked up on a key of some sort, and he ended up getting the monster jump," Lovullo said. "We have some young pitchers, and we're going to have some young moments."

Where the D-backs were fundamentally sloppy, the Padres were not. Manny Machado, who was hitting when Frazier took off, did not swing at what proved to be strike two in order to let Frazier get into scoring position.

Then Machado delivered a single to score Frazier with the go-ahead run.

"Look, they played good baseball there that eighth, and we did not," Lovullo said. "That was the difference in the game."