Ryan Mountcastle hit a grand slam among his two homers and drove in nine runs as the Baltimore Orioles rallied from a four-run deficit to defeat the visiting Oakland Athletics 12-8 on Tuesday night.

Mountcastle had a three-run shot in the fifth before the big blow in the seventh as part of a 3-for-4 effort.

The nine RBIs tied a single-game franchise record. Jim Gentile accomplished the feat in 1961, and Eddie Murray did so in 1985.

Austin Hays also homered and went 4-for-5 as the Orioles won for the second night in a row.

Shea Langeliers smashed a three-run home run to cap Oakland's five-run fifth, but a 7-3 lead wasn't enough, and the Athletics lost their sixth straight.

It was a rough home debut for Baltimore starter Grayson Rodriguez, Baltimore's top prospect, according to MLB.com. He allowed five runs on six hits and four walks in 4 1/3 innings while striking out six.

Bryan Baker (1-0) provided one scoreless inning in relief to pick up the win.

Oakland starter Kyle Muller was tagged for six runs in four innings, failing to record an out in the fifth, when he was charged with three of those runs. Sam Moll (0-1) took the loss.

The Athletics scored a first-inning run for the second night in a row, this time on Brent Rooker's two-out single.

Baltimore also scored in its first at-bat, with Hays doubling and later scoring on Mountcastle's sacrifice fly.

Oakland went back ahead, 2-1, on Jace Peterson's two-out single in the third.

Mountcastle provided a game-tying single in the third. In the fourth, James McCann doubled after Ramon Urias drew a leadoff walk to put the Orioles on top 3-2.

After Oakland's big rally that included Langeliers' second home run of the season, Mountcastle's fourth homer of the year, a three-run shot, closed the gap to 7-6.

Hays knotted the score at 7-7 with his solo homer with one out in the sixth before Mountcastle put the game away with his grand slam an inning later. It was Mountcastle's fifth homer of the season.

--Field Level Media