"You've just got to stay focused," Bass said. "You never know when you're going to pitch."
Luke Gregerson began the ninth looking for his ninth save.
Chris Johnson had a leadoff single for his third hit of the game and pinch hitter Ryan Wheeler followed with a grounder to second baseman Logan Forsythe, who dropped the ball as he ran toward the base and then extended his left leg toward the bag as he lay prone on his stomach reaching for the ball.
Johnson appeared on replay to push Forsythe's foot into the base on his slide, but second-base umpire Doug Eddings called Johnson safe.
Then the parade from the bullpen began.
"I'm going to need to ice my knees after I talk to you guys," Padres manager Bud Black said. "There are a lot of ways to get (a win) and that's one of them."
With the infield drawn in, Adam Eaton hit a grounder to second and Forsythe threw home to force Johnson. Black went back to the bullpen for the fifth time in as many plate appearances and brought on Bass, the Padres' eighth pitcher of the game.
Bass needed only four pitches to retire Hill.
"One save doesn't make you a closer," he said with a smile.
Black was most impressed with Layne and Vincent, who have 40 major league innings between them.
"That's a little bit of September baseball," Black said. "Those guys have been given an opportunity and for the most part I think they've shown well."
Jesus Guzman homered for the Padres, who dropped the first two games of the series.
Clayton Richard (14-12) allowed four runs and eight hits in six innings to raise his career record against Arizona to 6-0 -- including three wins in three starts at Chase Field over the past 10 weeks. He struck out three and walked one.
Eaton hit his first career home run and Hill also went deep for the Diamondbacks, who had won three in a row. Justin Upton had three hits and scored twice.
Diamondbacks starter Tyler Skaggs (1-3) pitched in and out of trouble while allowing four runs and seven hits over five innings. Skaggs, who reached the fifth inning for only the second time in his past three outings, walked three and struck out two.
"He gets an 0-2 count on Guzman then he tries to waste a fastball and throws it right where he doesn't want it," Arizona manager Kirk Gibson said. "That is a live and learn deal. He struggled."
Hill homered with one out in the first to make it 3-1 but the Padres came right back in the second when Forsythe doubled home Richard, who had reached on a fielder's choice.
Gibson helped nurse Skaggs through trouble in the fourth, visiting the mound with one out and two runners on.
"When I went out I told him, 'You are going to stay in the game. Let's take a breather and get your composure. It is time to make some pitches," Gibson said. "He got out of the inning. I feel that at this point in his career that's what he needed to do and he did it."
Upton tripled leading off the sixth and scored on Paul Goldschmidt's single to right. Goldschmidt went to second on a wild pitch and scored on a single to left by Johnson to make it 6-4.
Eaton hit a two-out homer in the seventh off Brad Brach to cut the lead to 6-5.
"It's kind of a mental check mark to get out of the way," Eaton said. "From when my experience when you get up here you look forward to those things and to get them out of the way so you can feel more comfortable."
After the game, the Padres activated closer Huston Street from the 15-day disabled list. "Just to finish healthy was always a goal," said Street, who missed 35 games with a left calf strain after earlier losing 29 games to a strained muscle. "I've wanted to pitch and play." ... Richard struck out the side in the third on 10 pitches for his only three strikeouts and threw 79 pitches total, his fewest in a win this season. ... Both teams had a little fun with their rookies after the game. Diamondbacks players were wearing women's clothing for their flight while Padres rookies were in "Olympic" attire -- boxing trunks, cycling shorts and tops and swim trunks, to name a few. ... Upton has seven extra-base hits in his past five games after hitting just five in his previous 25. ... Padres LF Carlos Quentin, who came out of Wednesday night's game with discomfort in his surgically repaired right knee, was held out of the lineup on Thursday and is day to day. ... Diamondbacks C Miguel Montero extended his franchise record with his 18th consecutive start. ... RHP Casey Kelly (2-1) will take the mound Friday for the Padres against San Francisco RHP Ryan Vogelsong (12-9). The Diamondbacks open a four-game wraparound series in Colorado with LHP Wade Miley (15-10) pitching against Rockies LHP Drew Pomeranz (1-9).