The Astros put up four runs in the 2nd inning with the very surprising help of an error by Cubs pitcher Kyle Hendrick, who has the best fielding card you can have with an E-1, CD-5.
The bottom of the order finished the rally with a Michael Brantley double and rare Corey Julks homer for the 4-0 lead.
However the Cubs got right back in it with a Patrick Wisdom 2-run homer.
The Astros were without ace reliever Ryan Pressly because he had face 5+ batters while getting tagged for the loss in Game 3, but former White Sox Kendall Graveman and Bryan Abreu retired the last six for the win.
The Astros lead 3 games to 1 and can clinch at Wrigley, or if not head back to Houston for Games 6 and 7.