Updated

Right-hander Edwin Jackson aims to erase an ugly result from his third start of the season tonight when the Washington Nationals head to Minute Maid Park to open a four-game series with the Houston Astros.

Jackson, who was born in 1983 in the former West Germany, was an 11-4 loser to the Astros when the teams met on April 19 in Washington.

Houston tagged him for five runs on seven hits in just five innings while scoring its lone win in six meetings.

Jackson is 2-1 with a 4.55 earned run average in 29 2/3 innings against the Astros.

He improved to 6-6 on the season with an 8-2 win at Milwaukee on July 26, but dropped back below .500 with a 3-2 loss to Philadelphia in his most recent start on Aug. 1.

In that game, the 6-foot-3, 205-pound Jackson allowed three runs on eight hits in 5 2/3 innings.

He's opposed by rookie southpaw Dallas Keuchel, who's been shelled in four straight outings after going 1-0 with a 1.35 ERA in his first three starts.

A complete-game winner over Cleveland in his second big-league outing on June 23, Keuchel went on to toss six innings of one-run ball against San Diego five days later before being tagged for four runs in a 6-4 loss at Pittsburgh on July 4.

He allowed seven, five and seven runs over 13 1/3 innings in three more starts in July, swelling his ERA to 5.77 in a composite 39 innings since his debut on June 17.

Keuchel has never faced the Nationals.

On Sunday in Washington, Stephen Strasburg tossed six scoreless innings as the Nationals dropped the Miami Marlins, 4-1, in the finale of a four-game series at Nationals Park.

Strasburg (12-5) bounced back nicely after a subpar outing against Philadelphia on July 31 in which he allowed six runs on eight hits over four innings.

This time out, he scattered three hits and fanned six with one walk in the win. The big righty also came up with a two-run single at the plate, helping the Nationals to their fourth win in five tries.

"I think I'm still learning how to pitch and call a game," Strasburg said. "(Sunday) was a big step forward for me in the process, but there's still a long way to go."

Adam LaRoche went 2-for-3 with a two-run single and Bryce Harper added a pair of hits in the victory.

Washington leads Atlanta by three games in the National League East.

In Atlanta, David Ross hit a solo homer, Paul Janish added a two-run single and the Braves downed the Astros, 6-1, in the rubber match of a three-game series.

Houston's Bud Norris (5-9), who has dropped eight straight decisions, was charged with four runs on seven hits - including Ross' solo shot in the second - with three walks and seven strikeouts over six frames.

"I felt good," said Norris. "All the ground balls got through. I got nothing I can do there. I'm making pitches, unfortunately they didn't go my way."

The Nationals took three of four games from the Astros when the teams last met in Washington back in April.

They've split season series for three straight years since Houston won, four games to two, in 2008.