J.A. Happ pitched six strong innings a day after being acquired and Chris Johnson hit a three-run homer as the Houston Astros began their post-Roy Oswalt era with their third straight win, a 5-0 triumph over the Milwaukee Brewers on Friday.

Acquired from Philadelphia on Thursday in the deal that sent Oswalt to Philadelphia, Happ (2-0) was impressive in his Astros' debut, limiting the Brewers to two hits and four walks while striking out six.

Jason Michaels gave Happ all the support he needed in the second with a leadoff homer, his sixth blast of the season. Michaels also ignited a rally in the fourth, drawing a two-out walk before Johnson belted a three-run shot two batters later for a 4-0 bulge.

Johnson's home run extended his hitting streak to 13 games, the longest by Houston rookie since Julio Lugo's 14-game streak in 2000.

Jeff Keppinger capped the scoring in the eighth with a solo homer for Houston, which improved to 4-3 on its nine-game homestand.

Manny Parra (3-8) lasted 5 1/3 innings for Milwaukee, surrendering four runs and four hits with three walks and six strikeouts.

Casey McGehee collected two of the four hits by the Brewers, who have lost three in a row following a five-game winning streak. Corey Hart returned after a five-game absence due to a wrist injury and went 0-for-3 with a walk.