Edwin Jackson threw a two-hitter for his fifth career complete game and Adam LaRoche added to his unusually strong start with a tiebreaking two-run double Saturday, helping the Washington Nationals win their fifth game in a row, 4-1 over the Cincinnati Reds.

Other than a rocky second inning, Jackson (1-0) was as efficient and effective as can be, striking out nine. He retired 16 consecutive batters in one stretch, until walking Chris Heisey leading off the eighth. After a visit from pitching coach Steve McCatty, Jackson got back in gear, striking out the side. And he finished with the flourish of a 1-2-3 ninth.

As if all of that weren't enough, Jackson even singled off Reds starter Homer Bailey (0-2).

He needed only 92 pitches, 65 of which were strikes.

Before an announced crowd of 35,489, Jesus Flores went 3 for 3 with an RBI while shrugging off a collision at the plate as a runner and Jayson Werth had two hits. The NL East-leading Nationals improved to 7-2, by far their best start since moving from Montreal to Washington in 2005.

Jackson's last complete game came July 16, 2011, for the Chicago White Sox against Detroit. He finished last season with the World Series champion St. Louis Cardinals, then signed a one-year free-agent deal with Washington.

Bailey went six innings, giving up three runs and seven hits. He also walked four — two apiece in the second and third innings, when Washington did all of its scoring off him. The biggest blow was LaRoche's drive to right-center in the third, breaking a 1-1 tie.

Accustomed to awful Aprils, and coming off an injury-shortened 2011, LaRoche added a single off reliever Sam LeCure ahead of Werth's run-scoring double in the seventh and is now hitting .333, with team highs of two homers and 10 RBIs.

LaRoche played in only 43 games last year because of an injured left shoulder that he had surgery on in June. That still left time to hit .190 in April with 10 RBIs — a total he's already matched after nine games in 2012. The first full month of baseball generally has been the cruelest month for LaRoche: From 2004-11, he hit .207 and averaged 10.9 RBIs in April.

"For whatever reason," LaRoche said before Friday's victory over Cincinnati, "it takes a while to get going."

Asked about the importance of producing early for a change, he said: "Personally, it's something you want to do. You don't want to get off to a slow start. More importantly, it's helping the team. It's helping us stay in some of these games and win some of these games. It's nice to be a part of it."

LaRoche also provides first base defense that, in the words of general manager Mike Rizzo on Saturday, is "as good as anybody." In the third, for example, LaRoche made a nice scoop in the dirt to complete the out when third baseman Ryan Zimmerman made quite a highlight-reel play, reaching high to barehand Zack Cozart's chopper and whipping a throw.

The Reds, meanwhile, continue to struggle at the plate: They've lost five of their past six games and have scored a total of 10 runs in that span. So far in three losses against Washington, Cincinnati has scored four runs in 32 innings.

Joey Votto, in his customary No. 3 hole, was the only Reds player in the in the same spot in the batting order Friday and Saturday. Four of the eight position players in the starting lineup changed.

But manager Dusty Baker said the switches were less about his team's problems scoring and more about the short turnaround: Friday's 13-inning loss finished after 11 p.m., and Saturday's game started about 17 hours later.

"Not lack of offense; lack of sleep," Baker explained.

Miguel Cairo started at third base for the Reds but left in the second inning with a strained left hamstring after doubling and coming around to score on Drew Stubbs' RBI single. Cairo, who was replaced Saturday by Wilson Valdez, is day to day.

Before Stubbs came through, the Reds had been 1 for 18 with runners in scoring position during this series.

And after Stubbs came through, the Reds reverted to their punchless ways: The next batter, Devin Mesoraco, grounded into a double play, beginning Jackson's perfect 16-hitter string.

NOTES: Nationals CF Rick Ankiel came off the DL to make his season debut, batting seventh. He'd been out since spring training with a left quadriceps injury. ... Reds 2B Brandon Phillips (left hamstring) was out of the lineup for the fifth consecutive game. He's expected to return Sunday