Three batters later, Wilson Ramos hit a monster three-run homer that went completely out of the stadium in left field.
But the Astros would make it a one-run game by the fifth inning. With Tanner Roark on the mound, Marc Krauss put Houston on the board with a solo home run in the third.
An inning later, the Astros scored two unearned runs off Christian Garcia. George Springer reached base on a three-base error by Span in center field. Springer then scored on a sacrifice fly by Marwin Gonzalez. Carlos Corporan came across with the Astros' third run on a single by Robbie Grossman.
Reliever Rafael Soriano, appearing in his first game of the spring, allowed a two-run double to Corporan to make it a 6-5 game in the fifth.
Zach Walters would give the Nationals a three-run cushion by hitting a Josh Zeid pitch to left field for a single, scoring Will Rhymes and Jeff Kobernus. The runs were charged to right-hander Eric Williams.
Oberholtzer went two innings, with five of the six runs earned, while Roark gave up four hits and one run with three strikeouts over 2 2/3 innings.
Up next for the Nationals: The Nationals play split-squad games against the Braves and Cardinals on Saturday, both of which can be heard on Gameday Audio. Chris Young will get the start against the Cardinals in Jupiter, Fla., at 1:05 p.m. ET, while Taylor Jordan gets the nod against the Braves at Space Coast Stadium at 1:05.
Bill Ladson is a reporter for MLB.com and writes an MLBlog, All Nats All the time. He also could be found on Twitter @WashingNats. This story was not subject to the approval of Major League Baseball or its clubs.