BOSTON -- Bryce Harper homered and drove in three runs while Stephen Strasburg matched a season high with 13 strikeouts to lead the Washington Nationals to a 7-4 opening victory over the Boston Red Sox in the interleague series.

Ian Desmond doubled in a pair and Danny Espinosa added an RBI and two runs scored for the Nationals.

Boston has dropped three of its last four to fall back to .500 at 29-29.

Harper sparked a three-run rally in the third with a double, sending Espinosa to third. Ryan Zimmerman followed with an RBI single and Desmond capped the spurt with a two-run double, giving Washington a 3-2 lead.

Harper highlighted another three-run rally in the fourth, driving a 1-1 fastball to the deepest part of the ballpark, just to the right of the 420-foot sign in center field, for his sixth homer. The 19-year old finished a triple shy of the cycle in his Fenway Park debut.

Strasburg (7-1) allowed two runs in the second inning but shut down the Red Sox the rest of the way, allowing four hits while walking a pair in six innings.

Boston loaded the bases in the sixth but Strasburg struck out Jarrod Saltalamacchia and Kevin Youkilis to end the threat.

Tyler Clippard got the final two outs for his sixth save.

Felix Doubront (6-3) took the brunt of the damage for the Red Sox, allowing six runs and eight hits in four innings.

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GAME NOTEBOOK: Boston slugger Adrian Gonzalez hit his 200th career home run in the eighth, driving a blast to deep center field off Nationals reliever Ross Detwiler. ... Youkilis was ejected for arguing the called strike call to end the sixth inning. ... Gonzalez was robbed of a solo homer run in the third inning, when Washington RF Xavier Nady reached into the bullpen and pulled the ball back. ... Boston RH Daisuke Matsuzaka will make his season debut on Saturday, one day short of the one-year anniversary of his Tommy John surgery. The Nationals will counter with LH Gio Gonzalez.