White surrendered three more two-out runs in the third on three consecutive hits, as the Mets chased him after 2 2/3 innings of work.
Marlon Byrd doubled to straightaway center with one out and scored on Davis' broken-bat RBI single to left. Duda followed with an RBI double to left. John Buck capped the scoring with an RBI double to right-center.
Houston trimmed the deficit to 4-2 in the fourth on Carlos Pena's first-pitch, two-run homer to left off left-hander Rob Carson. Fernando Martinez began the inning with a walk.
But the Mets countered with a four-run fourth on six hits, a sacrifice fly and throwing error to extend their lead to 8-2. Each batter came to the plate against left-handers Kevin Chapman and Rudy Owens.
Anthony Recker doubled to left to start the frame and scored on Ruben Tejada's RBI single up the middle. Wilmer Flores also singled, and the runners moved up a base on Byrd's swinging bunt to the pitcher. On Justin Turner's flyout to left, Martinez's errant throw plated both Tejada and Flores. Davis, Duda and Buck collected back-to-back-to-back two-out singles. All told, the Mets set a team-high in Grapefruit League play this spring with the nine runs scored.
Marc Krauss' one-out sacrifice fly to left off right-hander Collin McHugh drove in Brandon Barnes, who singled to lead off the seventh and advanced on a pair of wild pitches.
Mets starter Jeremy Hefner (1-0) pitched three scoreless innings, allowing just one hit, with a pair of strikeouts and one walk. He threw 36 pitches -- 23 for strikes.
Up next for Mets: Right-hander Shaun Marcum, who signed a one-year deal at the end of January, will make his second spring start for the Mets as they battle the Cardinals on Sunday. He hopes to bounce back from a two-inning outing, in which he allowed three runs on four hits, including a two-run homer to Chris Snyder. St. Louis counters with Jaime Garcia for the 1:05 p.m. ET contest at Roger Dean Stadium in Jupiter.
Christina De Nicola is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.