Buchholz (1-2) allowed one run on eight hits and struck out six in his fourth start for the first-place Express (74-52).

The 24-year-old right-hander spent the first four months of the season with the Houston Astros and had given up at least four earned runs in each of his previous three starts for Round Rock.

He lowered his ERA to 5.33 as the Express equaled their win total from last season. Prior to 2005, Round Rock was the Double-A affiliate of the Astros.

House staked Buchholz to an early lead by launching a two-run homer, his third, in the opening frame. He also doubled and scored in the fourth, when the Express opened a 4-0 lead. Humberto Quintero tripled and drove in two runs, while Cody Ransom drew three walks and scored twice.

Cubs starter Sean Marshall (0-2) surrendered six runs on four hits in 5 2/3 frames, striking out six and walking four.

Augie Ojeda led off the fifth with single and scored on Felix Pie's infield hit to provide the lone run for Iowa (63-63), which lost its fifth straight. --Christopher Heine/MLB.com