Nationals 9, Cubs 1: Gio Gonzalez tossed seven innings of three-hit ball to match R.A. Dickey with his major league-leading 18th win, and Washington continued its barrage of visiting Chicago with a second consecutive six-homer game to win for the seventh time in eight outings.

The Nationals have claimed the first three games of the four-game series and five of six meetings this season. They remained 7 1/2 games clear of Atlanta in the National League East.

Gonzalez (18-7) didn't allow a hit until Darwin Barney led off the sixth with a clean single past diving third baseman Ryan Zimmerman. By then, he had a huge cushion. Adam LaRoche's RBI single gave Washington a 1-0 lead in the first, Roger Bernadina and Bryce Harper homered on consecutive pitches in the third, and LaRoche capped the four-run third with a two-run blast - his fourth homer of the series.

Harper added another shot into the second deck in right in the sixth to make it 6-0, and Ian Desmond and Danny Espinosa hit back-to-back blasts in the seventh.

Cubs starter Chris Volstad (2-10) absorbed most of the damage, allowing five runs on nine hits over five innings to snap his modest two-game winning streak.

Gonzalez won for the fifth time in his last six starts in beating the Cubs for the first time in three tries. He struck out nine and extended his scoreless streak to 16 innings.

Chicago rookie Anthony Rizzo broke up the shutout with his 11th homer with one out in the ninth.

The Cubs have lost 29 of their last 35 games. They've dropped seven straight and 16 of 17 on the road.

GAME NOTEBOOK: The Nationals are the third team in the live-ball era (since 1920) to hit six or more home runs in consecutive games. … Zimmerman extended his hitting streak to 10 games, his longest of the season. … LaRoche reached base in nine straight plate appearances, going 7-for-7 with two walks over the past two games before striking out in the seventh. … Harper is the youngest player with at least 17 homers in a season since Tony Conigliaro in 1964. Harper has hit seven home runs in his past 18 games. … Cubs manager Dale Sveum was ejected by home plate umpire Larry Vanover in the fifth inning.