Leading off the fourth, Boston's Jacoby Ellsbury worked the count full, then laced a clean single to left, the first hit for either team in a crisply played game. Dustin Pedroia followed with a line drive to left that went for a run-scoring double and a 1-0 Red Sox lead. Adrian Gonzalez flew out to left, with Pedroia successfully testing left fielder Mark DeRosa's arm to advance to third. David Ortiz swung at the first pitch he saw and grounded to second, scoring Pedroia on the inning's second out. Kevin Youkilis took a called third strike to end the frame.
It's 2-0 Red Sox heading to the bottom of the fourth. The Nationals have gone down in order for the first three innings against Boston righty Clay Buchholz.
Update: Jackson's day is done and he leaves trailing 5-0 with two down in the fifth. Pedroia just hit a two-run double over the head of right fielder Jayson Werth. Earlier, Ellsbury's RBI single made it 3-0 after the Red Sox put runners on second and third with two away.
Sean Burnett came on and yielded a single through the right side, scoring Pedroia for a 6-0 lead.
Jackson worked 4 2/3 innings, allowing six runs on five hits with one walk and two strikeouts. He finishes spring with a 6.18 ERA in seven starts. He threw 73 pitches, 46 for strikes.
Buchholz has retired the first 12 Washington hitters in order.
Update: Adam LaRoche singled down the right field line leading off the fifth, the Nationals' first hit of the game.