Updated

Dave Sappelt went 2-for-5, driving in three and scoring once to account for all of the Cubs' runs, steering Chicago to a 4-1 victory over the Houston Astros in the first of a three-game set.

The Cubs, who have won four games in a row on the road and overall, are making their final trip to Houston while the Astros are members of the National League. Houston will join the American League West Division next season.

"Winning is always fun, so for us to win four in a row we want to keep it going," Sappelt said.

After having his two-game winning streak snapped in Washington, Chris Volstad (3-10) got back on track and earned his first road victory of the season. Although he walked five batters, he allowed just one run on four hits through five innings of work.

Jason Castro's RBI-single in the fourth brought home the only run for the Astros. Starter Dallas Keuchel was pinch-hit for later that inning, ending his outing after just four innings of work. He allowed one run on six hits.

Fernando Rodriguez (1-10) took the loss. While pitching to Darwin Barney in the sixth, he threw a wild pitch that allowed Sappelt to score the go-ahead run from third to give the Cubs a 2-1 advantage.

Carlos Marmol worked around a base hit from Fernando Martinez in the ninth, striking out Brett Wallace to end the game and earn his 19th save of the season.

"We got a lot of guys on base, but we failed to get those hits in scoring position," Astros outfielder Justin Maxwell said.

The Cubs struck first when they put up a score in the top half of the second. Welington Castillo drew a two-out walk, advanced to second on a base hit from Josh Vitters and came around to score on an RBI-double from Sappelt.

The Astros answered back with a run two innings later when Maxwell led the inning off with a triple. Jason Castro brought him home with a single on the ground to right to tie the game at one.

The Cubs nearly tacked on the go-ahead run in the fourth. Volstad hit a two- out single after a leadoff base hit by Castillo. Joe Mather came through with a line drive single as well, but left fielder J.D. Martinez gunned down Castillo at the plate to end the inning.

After Sappelt scored the Cubs' second run in the sixth, he drilled a two-run double the following inning to score Starlin Castro and Castillo. Castro doubled after Alfonso Soriano led the inning off with a walk. Astros pitcher Hector Ambriz then intentionally walked Castillo to load the bases, but got Vitters to ground into a double play, forcing Soriano out at home and him at first base. Sappelt was the following batter and brought the two base runners home with his hit to center.

Game Notes

Marmol has successfully converted his last 18 save opportunities dating back to May 2 ... Starlin Castro extended his hitting streak to eight games ... Keuchel has gone 11 straight starts without a win.