Phoenix, AZ (SportsNetwork.com) - Tommy Medica drilled a tiebreaking solo homer in the top of the eighth inning to send the San Diego Padres to a 4-3 victory over the Arizona Diamondbacks in the middle contest of a three-game set Tuesday at Chase Field.

Gerardo Parra brought Arizona even with a run-scoring single in the seventh, but with two outs in the eighth, Medica clubbed an 0-1 offering from Evan Marshall (2-1) deep into the seats in left.

Kevin Quackenbush (1-1), who served up A.J. Pollock's game-winning two-run homer Monday, recorded the final out in the seventh and spun a 1-2-3 eighth before Huston Street retired the side in order in the ninth to nail down his 15th save of the season.

Medica finished 3-for-4 with two RBI, while Chris Denorfia and Chase Headley drove in a run apiece for the Padres, who have won three of their last five games.

Martin Prado stroked his first homer of the season for the Diamondbacks, who had won three of their last four games coming into the contest.

Prado's solo blast staked Arizona to a 1-0 lead in the second, but San Diego scored three times in the third to seize control.

Arizona starter Wade Miley struck out counterpart Eric Stults to start the third before the Padres strung together four straight singles, with Denorfia and Headley each knocking in a run.

Miley snapped the string by fanning Jedd Gyorko, but Medica came through with a two-out single to right, scoring Carlos Quentin for a 3-1 lead.

The Diamondbacks sliced the margin in half in the sixth, as Paul Goldschmidt worked a leadoff walk before scoring on Miguel Montero's double to right. Prado's groundout moved Montero to third, but Stults induced consecutive fly outs to keep the margin at one.

The San Diego southpaw ran into more trouble in the seventh, as Cliff Pennington smacked a leadoff double to end Stults' outing. Dale Thayer entered from the bullpen and fanned back-to-back hitters, but Pennington was able to swipe third.

Alex Torres then took over for Thayer and was greeted by Parra, who ripped a single to left to plate Pennington and tie the game at 3-3.

Goldschmidt then reached on catcher interference and Montero walked to load the bases, but Quackenbush came on and grounded out Prado to end the frame.