CINCINNATI -- The Cincinnati Reds hit six home runs, including two each by Zack Cozart and Todd Frazier and a pinch-hit grand slam by Xavier Paul, in a 15-0 victory over the previously unbeaten Washington Nationals in the opener of a three-game series at Great American Ball Park.
Cozart hit a three-run blast in the third and had five RBI. He and Frazier hit back-to-back home runs on consecutive pitches from Washington starter Dan Haren in the second inning. Frazier added a two-run homer in the seventh, and Shin-Soo Choo added a solo homer in the fourth.
The six homers were one shy of the Reds' franchise record at Great American Ball Park.
Washington, which outscored the Florida Marlins 11-1 in a season-opening three-game series at Nationals Park fell behind early in Friday's game and were unable to rally against the Reds' pitching.
Reds starter Homer Bailey (1-0) allowed just two hits and struck out six over six innings. He walked three batters but was in control throughout.
Haren (0-1), who was signed as a free-agent in December, gave up six earned runs and nine hits including four homers in four innings.
Paul's pinch-hit grand slam came off Henry Rodriguez in a seven-run seventh inning, during which Cincinnati sent 11 batters to the plate.
Washington managed only five hits.
Nationals second baseman Danny Espinosa ended an 0-for-11 streak, going 2-for-3 with a double.
Bryce Harper went 0-for-4, ending his career-best 12-game hitting streak which dated back to Sept. 24.
It took just two pitches from Haren for Cincinnati to grab a 2-0 lead in the second inning.
With one out, Frazier launched Haren's first pitch 437 feet into the bleachers in left field. On the next pitch Cozart hit his first home run of the season.
Bailey, looking to build off his strong finish to the 2012 season that included a no-hitter at Pittsburgh, had six strikeouts through four innings Friday.
Cozart's second round-tripper, a three-run blast on an 0-1 pitch from Haren, put Cincinnati ahead 5-0 in the third inning.
Choo added a solo homer in the fourth, making the score 6-0. A video replay confirmed the ball cleared the wall before being corralled by a fan.
NOTES: Cozart recorded his first career multi-homer game. .. Haren gave up four home runs in a game for the first time since June 9, 2012, at Colorado. .. The Reds used the same lineup for the third straight game. Last season, they didn't use the same lineup in three straight games until the final three games of the National League Division Series. .. Entering Friday's action, Washington was the lone remaining undefeated team in Major League Baseball for the first time since the 1913 Nationals of the American League.