Astros 8, Cubs 4: Bud Norris pitched seven scoreless innings and Jason Castro and Chris Johnson each hit three-run homers as Houston handed Chicago its seventh consecutive loss.

Castro gave the Astros the lead for good when he went deep to right against Matt Garza (2-2) in the second inning. Carlos Lee added an RBI single in the third before coming in on a two-out blast to center by Johnson.

That was more than enough support for Norris (5-1), who scattered five hits and struck out eight to win his fourth straight start. He stranded runners on third base in both the first and fourth innings before retiring nine of the last 10 batters he faced.

The Astros, who stayed within four games of St. Louis in a crowded National League Central, finished with just eight hits but took full advantage of nearly every opportunity they had, leaving only one runner on base in the first six innings.

Jed Lowrie hit a two-out solo homer in the seventh for Houston.

The Cubs finally got on the board in the ninth inning. Reed Johnson and David DeJesus each singled in a run before both came in on Blake Lalli's first career base hit.

Garza lasted just three innings, yielding five hits and two walks while striking out two.

GAME NOTEBOOK: Norris has allowed just one earned run in 26 innings during the month of May. ... Houston has won nine straight when scoring at least four runs. ... Garza’s ERA ballooned from 2.58 to 3.72. ... Castro’s homer was his first of the season and the third of his career.