Sanchez's three-run double in the fifth inning put Pittsburgh ahead, leading Duke and the streaking Pirates past the Atlanta Braves 5-0 Monday in the first game of a doubleheader.
Duke (2-2) shook off five walks and three errors behind him to limit Atlanta to five hits over six innings, and the Pirates won their sixth in a row -- their longest winning streak since taking 10 consecutive games from June 25-July 5, 2004.
The Braves lost their seventh straight on the road. They have the majors' best home record (14-4) and worst road mark (4-14).
Atlanta has lost three in a row in Pittsburgh after sweeping a six-game homestand against the Reds and Padres.
"I have no clue while we struggle on the road," Braves rookie starter Jair Jurrjens said. "It's a crazy thing a team goes through during a season and I hope we snap out of it quick, because we need to win some games on the road. Something on the road just doesn't click with us right now."
What is clicking for the Pirates is their starting pitching, which is 4-0 with a 2.29 ERA during the winning streak. Duke was constantly in trouble, with at least two runners reaching in all but one inning, but he got key outs when he needed them while stranding 10 runners.
"The big key was most of the runners came when we had two outs already, so you can focus on getting that one out. It made it a little easier," Duke said.
"Zach's keeping the ball down, using his sinker and he's getting a lot more ground balls," manager John Russell said. "He's going to give up some hits, but he attacks the zone down with his sinker, mixes in some off-speed pitches, and makes them hit it on the ground."
Duke hadn't won since June 12, a span of 12 outings over two seasons, until beating the Giants 12-6 by allowing three runs over 7 1/3 innings on Tuesday. The left-hander hadn't won successive starts since beating the Brewers and Mets, respectively, on Sept. 11 and 17, 2006, but has allowed three runs or fewer in six of eight starts this season.
After Duke struck out, Sanchez -- 10-for-24 (.417) with eight RBIs as a leadoff batter since moving up one spot in the order last week -- cleared the bases with a double to right-center.
"I don't think it makes any difference where he hits," Duke said. "He's steady Freddy, that's what he does."
Jurrjens said, "The pitch, I thought, was a good pitch, a two-seam fastball outside, but he's a good hitter and he hit it for a double. It cost us the game."
Braves 1B Mark Teixeira left in the fourth inning with back spasms on a cloudy, chilly 48-degree day. ... Pirates RF Xavier Nady didn't start for the first time since April 11. ... The doubleheader resulted from a rainout Sunday. ... Pittsburgh leads the season series 5-1. ... The Pirates have won their last seven in PNC Park and are 12-7 at home. ... Pittsburgh had gone 53 innings and six games without making an error until committing three in the first five innings. ... Braves reliever Jeff Bennett hit Michaels in the sixth with an inside pitch that popped open the top three buttons of Michaels' jersey. ... Atlanta's Gregor Blanco reached base four times on two singles and two walks.