The Arizona Diamondbacks' weary relief corps can certainly relate.Following a 15-inning victory on Sunday afternoon, the Padres head to Phoenix looking to further derail the hopes of the fading and potentially drained Diamondbacks.The Padres (59-71) put their bullpen to work early on Friday after starter Edinson Volquez couldn't make it out of the first inning. By the time San Diego finally won Sunday's game in the bottom of the 15th on Nick Hundley's single, its relievers had posted a 0.47 ERA over 19 innings against the Cubs."Any time you go long like that it adds a little more, it's a special win," Hundley said. "Losing a game like this takes a little bit more out of you, and winning it builds momentum."The Diamondbacks, who are returning home from a 10-game road trip, know something about exhaustion.Arizona's bullpen was needed for 12 innings in Saturday's 12-7, 18-inning marathon win over Philadelphia, and in all totaled 40 frames -- posting a 2.48 ERA -- during its 4-6 trip.The Diamondbacks lost four of their last five away from Phoenix, and are 9 1/2 games behind NL West-leading Los Angeles and seven behind Cincinnati for the second wild-card spot."It was a bad trip," manager Kirk Gibson said after Sunday's 9-5 loss. "We have a big game (Monday). We have to try to get some rest tonight and play a good game (Monday)."Gibson will certainly be hoping his bullpen isn't needed as much as it was in Brandon McCarthy's last start. McCarthy (2-8, 5.44 ERA) lasted just 2 1/3 innings Wednesday, yielding seven runs in a 10-7 loss to Cincinnati.He's 0-4 with a 6.98 ERA in four starts since returning from a two-month stint on the disabled list."I felt like I didn't have anything," McCarthy said. "I needed to get deeper and not let it become a train wreck."McCarthy's last win came against the Padres on May 24, when he held them to one run and five hits in seven innings.That was a rare win for Arizona in this season series. San Diego has taken eight of 12 from the Diamondbacks, including five of the last six.The Padres on Monday will turn to the pitcher who delivered their most recent victory against Arizona. Tyson Ross (3-6, 2.85) tossed eight innings of three-hit ball in a 1-0 win at Chase Field on July 28.Ross is 3-0 with a 0.86 ERA in three road outings since joining the Padres' rotation after the All-Star break, and he hasn't allowed a homer in that stretch as he heads into his second start in Phoenix."If anything, I try and stay down in the zone more," Ross told the team's official website of pitching in Arizona. "That's always a key when you're pitching -- being down. When you're in those hitter's ballparks, you really try and stay as low as possible. You need to limit hitters getting something elevated to hit."Much to the relief of manager Bud Black and the San Diego bullpen, the right-hander has gone at least six innings in all six of his second-half starts. His outing Tuesday against Pittsburgh -- five runs allowed over 6 1/3 in an 8-1 loss -- was his worst of that stretch, however.The Padres have given Ross a total of six runs in his last five outings, but he's not the only pitcher they're having trouble supporting. San Diego is hitting .155 with runners in scoring position since Aug. 6, with Jedd Gyorko (3 for 21) and Chase Headley (0 for 14, six strikeouts) the primary culprits.The Padres' 3.19 runs per game in August are the majors' fewest even though their overall batting average (.255) is 15th.