They still aren't scoring much, but their last game proved they have the ability to win unconventionally.The Padres try to have a better showing against Roark this time around as they open a three-game series with the visiting Nationals on Friday night.San Diego (27-33) has totaled eight runs and 12 hits over its last four games and ranks last in the majors in runs (191), batting average (.221) and hits (437).Its only hit Wednesday came on a bunt single from Everth Cabrera in the first inning, but it took advantage of nine walks to beat Pittsburgh 3-2. The Padres scored on a sacrifice fly, an error and a bases-loaded walk."You never know what's going to happen in a big league game," manager Bud Black said. "Anytime you win it's great, but when you win a game like that where you only get one knock, it's a pretty good one. Feel good about it."San Diego had three hits off Roark (3-4, 3.25 ERA) in a 4-0 defeat April 26, as the 27-year-old completed the best start of his short major league career.The right-hander enters this game having lost his last three starts, though that's not indicative of how well he's pitched recently. He's 1/3 with a 2.20 ERA over his last five outings after giving up one run in seven innings of a 2-0 loss to Texas on Sunday.Roark has pitched at least six innings in eight of his 11 starts. The only run he allowed against the Rangers came on a homer in the seventh."It was just a bad changeup," Roark said. "That's how it's been the past couple games, just one pitch. I've got to eliminate that from my repertoire."He'll be opposed in this game by Tyson Ross, who labored through his last outing but still pitched effectively.Ross (6-4, 2.85) gave up two runs -- one earned -- and struck out five in six innings of Saturday's 4-2 win over the Chicago White Sox. It marked the fifth time in his last six starts that he gave up one earned run, but he didn't feel like he pitched as well as he expected."It was a battle," Ross said. "Anytime you can find a way to get outs when you don't have your best stuff, that's what pitching's all about."Ross allowed one earned run in six innings of relief over three outings against the Nationals (30-28) last season. The right-hander will be making his first career start against Washington, which begins a 10-game road trip.The Nationals completed a three-game sweep of Philadelphia with Thursday's 4-2 victory."We have a really hard road trip coming up against some really good teams," said manager Matt Williams, whose team has won five of six. "Without going too far, we're happy with where we're at it right now and the way it's gone. We have to continue to push."Ryan Zimmerman drove in a run Thursday and is hitting .364 in 13 games this season. He went 4 for 11 with two doubles and two RBIs in the series after missing 44 games with a fractured right thumb.Zimmerman is batting .383 with seven homers and 17 RBIs in his last 13 against the Padres. He missed a four-game series split between these clubs April 24-27 in Washington.