The Giants hope that trend continues Saturday night when they try to deny Arizona Diamondbacks rookie Wade Miley his 16th win.San Francisco maintained its 7 1/2-game lead over the Dodgers in the NL West with a 6-2 win Friday while keeping Arizona 4 1/2 games behind St. Louis for the league's second wild-card spot.Hunter Pence's grand slam in a five-run third inning proved to be the difference.With Friday's victory, San Francisco (82-62) has won 11 of its last 13 road games and is 22-7 away from home since July 17. The Giants have averaged 6.4 runs over those 29 road games and scored 23 over the last three.Home and away, Pence is coming up big. He's driven in 18 runs over the last 15 games and has 11 RBIs in six games against the Diamondbacks (71-73) this year.He's more concerned with improving a .233 batting average since joining the Giants, however."I need to get more hits is what that tells me," Pence said, "Make them pitch to (Buster) Posey with runners on."In contrast to the Giants' road success, Arizona continues to struggle at the plate at home, totaling 19 runs while going 2-7 in its last nine at Chase Field.It's scored eight runs in the last four games overall, and stranded 15 runners Friday."We certainly had our opportunities," manager Kirk Gibson said. "A lot of plays we didn't play very well tonight. We made it harder on ourselves and we didn't capitalize on the opportunities we did have."Trying to make a move in the wild-card standings, the Diamondbacks turn to Miley (15-9, 3.07 ERA) on Saturday as he looks to become the first NL rookie since Jason Jennings with Colorado in 2002 to win 16 games.Miley has won three of his last four decisions, although he labored his last time out. The left-hander was helped by Arizona's bats in an 8-5 win over San Diego last Saturday after giving up five runs and eight hits over 5 1/3 innings."I got frustrated early and really stayed frustrated," Miley told the Diamondbacks' official website. "I never really calmed down and got in a rhythm. That's what happens. Sometimes you get mad and it helps out, but I was just flying open, trying to throw the ball as hard as I could, leaving it up."Miley made his season debut against the Giants on April 8, pitching four hitless innings of relief. This will be his first start versus San Francisco.The Giants counter with Barry Zito (11-8, 4.33), who will look to build off one of his better starts of 2012 while trying to improve to 3-0 against the Diamondbacks this season.Zito gave up four hits in 6 1/3 innings of a 4-0 win over the Dodgers on Sunday. The left-hander had gone a combined 7 1/3 innings over his previous two starts, allowing seven runs and 14 hits.Despite Zito's inconsistency, the Giants have won his last seven starts, offering 7.17 runs of support per nine innings. He is 3-0 with a 4.54 ERA during that span, including a start against the Diamondbacks on Sept. 3, when he was charged with four runs in five innings of a 9-8 victory in 10 innings.Zito is 3-4 with a 5.86 ERA in 11 career games at Arizona, but he held the Diamondbacks to three runs over six innings in a 7-3 win May 13.