Orioles 12, Cardinals 2: J.J. Hardy went deep twice and Manny Machado added a three-run shot as host Baltimore hit a season-high six home runs en route to victory in the opener of the three-game interleague series.

Adam Jones, Chris Davis and Ryan Flaherty also homered for the first-place Orioles, who maintained their five-game lead over the New York Yankees in the American League East. Nick Hundley collected three hits and an RBI while Chris Tillman (9-5) allowed two runs and four hits while striking out seven in 6 2/3 innings, marking the 12th consecutive start in which he has yielded fewer than four earned runs.

A.J. Pierzynski belted a two-run homer for the Cardinals, who fell two games behind first-place Milwaukee in the National League Central but remained even with San Francisco for the second wild-card spot. Justin Masterson (5-7) was tagged for five runs on seven hits and three walks in two-plus frames and has surrendered 10 runs over eight innings in two starts since being acquired from Cleveland.

Thwarted in the first inning after loading the bases with none out, Baltimore scored in each of the next five frames, chasing Masterson in the third. Hundley opened the scoring in the second with RBI single and Machado belted a three-run homer two batters later for a 4-0 lead. Hardy led off the third with his fifth blast and added a three-run shot off Nick Greenwood an inning later to make it an eight-run advantage.

Jones belted a two-out solo homer in the fifth and Davis greeted Sam Freeman with a leadoff shot in the sixth. Following a walk to Hardy, Flaherty deposited an 0-1 pitch over the left-field wall to increase the lead to 12-0 before St. Louis finally got to Tillman in the seventh with Pierzynski's blast.

GAME NOTEBOOK: Davis' home run was the 150th of his career while Jones' blast was his 86th at Camden Yards, pushing him past Cal Ripken Jr. for fourth place in the ballpark's history. ... St. Louis traded RHP Angel Castro to Oakland for cash. ... Greenwood was recalled from Triple-A Memphis earlier in the day after RHP Jason Motte (back) was placed on the 15-day disabled list. ... In addition to the first inning, Baltimore also failed to score after loading the bases in the third and sixth.