BOSTON -- Livan Hernandez struggled through his shortest outing of the season, leaving him searching for answers.
While Wakefield cruised, Hernandez (5-8) left the game after 1 2/3 innings and watched his ERA soar to 5.64.
"I'm worried about him," Nationals manager Frank Robinson said. "This is the way he has been except for two or three starts this year, and he has just not been consistent enough."
Hernandez gave up six runs and eight hits with two walks. He has given up 14 runs in his past three starts.
"They beat me bad," Hernandez said. "People have to understand that I can't be great every year. Boston is a great team and everybody knows that. My ERA is a little tough, but there is a lot of baseball left to be played."
Wakefield (5-8) won for the second time in his past seven starts, allowing one run and four hits. It was his first interleague victory at Fenway Park since 2000. Wakefield walked one and struck out four, escaping trouble in the sixth inning.
Boston has scored six runs in Wakefield's eight losses this season.
"It was unbelievable [the run support]," Wakefield said. "I have always said that it makes our job easier when we get some runs on the board early."
The Red Sox, who have won 11 of their past 12 interleague games, finished with a season-high 17 hits.
"Even when we were losing earlier in the season, we were still playing well," Nationals closer Chad Cordero said. "We just haven't been able to keep their hitters down the last few games."
Alex Cora was 3-for-3 with three runs. He is 19-for-50 (.380) over his past 17 games.