By JEFF MEZYDLO
(AP) -- Strong starting pitching has been a key reason for the Washington Nationals' early success. The rotation has certainly had its way with the San Diego Padres of late.
The Nationals look to complete a three-game sweep of the Padres with a fifth straight victory Thursday night at Petco Park.
Jordan Zimmermann threw four shutout innings Wednesday to help Washington (14-4) set a club record with 26 straight scoreless frames from its starters. Orlando Hudson snapped the streak with a solo homer in the fifth, but the Nationals rolled to a 7-2 win.
First in the NL East, Washington has won six straight series to open the season thanks to a 1.71 ERA from its starters.
"It's been outstanding," manager Davey Johnson said. "Six or seven innings putting up zeroes, low hits, very few mistakes. They're kind of competing against each other when they go out there - who's going to throw the better outing? It's been fun to watch."
Washington's starters have posted a 0.86 ERA during a five-game winning streak over San Diego in which the Nationals hold a 16-5 scoring advantage.
"You look at a 2.20 ERA (overall this season) when you are giving up two runs per game over (18) games, you are going to have nice results," Padres manager Bud Black said.
Washington turns to Edwin Jackson (1-1, 4.26 ERA) to help complete the sweep Thursday.
After giving up two hits in a complete-game 4-1 win over Cincinnati on April 14, Jackson was tagged for five first-inning runs before throwing four scoreless frames during an 11-4 loss to Houston last Thursday.
"(Jackson) was throwing all right, but his location was pretty much down the middle," Johnson told the Nationals' official website. "(After the first inning) he turned it up a notch. He was unhittable the rest of the way."
The right-hander has been very hittable while going 0-3 with a 5.16 ERA in five career starts versus San Diego.
Adam LaRoche had three hits Wednesday as the Nationals matched their season high for runs. The veteran first baseman has hit .350 (7 for 20) in his last five games versus San Diego.
While Washington owns the best record in the NL, the Padres (5-14) have the worst. Batting .211, San Diego has scored two or fewer runs nine times.
"You can't think the season (is lost) in April," Black told the Padres' official website. "No matter if you're in first place or last place."
Despite his team's offensive struggles, Hudson has batted .310 (9 for 29) in the last eight games. He's 2 for 2 with a double and a walk versus Jackson.
Edinson Volquez (0-2, 4.30) looks to help the Padres avoid the sweep while trying a fifth time for his first win with his new team.
The right-hander carried a two-hit shutout into the seventh, but he gave up three runs and did not get out of the inning in Friday's 4-1 loss to Philadelphia. Volquez walked three, giving him 15 in 23 innings.
He's 1-1 with a 9.72 ERA in two starts against the Nationals but has not faced them since 2010.
Updated April 25, 2012