MIAMI -- When Anibal Sanchez earned his first major league win last month at Yankee Stadium, he was unsure whether he would get another start with the Florida Marlins or return to the minors.

His spot on the team -- and in the rotation - is now more secure.

The rookie extended his shutout streak to 18 1/3 innings, allowing one hit in seven-plus innings Wednesday to help Florida beat the Washington Nationals 1-0.

Acquired last November in the trade that sent Josh Beckett and Mike Lowell to the Boston Red Sox, Sanchez started the season at Double-A Carolina and was recalled June 25. The right-hander pitched 5 2/3 scoreless innings against the New York Yankees in his debut.

"I didn't know if I was going to stay in the big leagues," he said. "I'm pitching with more confidence now."

Said manager Joe Girardi: "He should be confident, the way he has thrown."

Sanchez is 3-0 with an ERA of 3.41, including a 1.46 ERA in four starts. He beat Roger Clemens in his last outing and has given up only three hits in his past 14 innings.

The Nationals' lone hit off Sanchez was a line drive to right-center by Austin Kearns leading off the third. Washington's Ryan Zimmerman went 0-for-4, ending his 17-game hitting streak, a franchise rookie record.

Joe Borowski pitched the ninth for his 19th save in 21 chances. With runners at the corners, he struck out Marlon Anderson and retired Kearns on a 400-foot fly to center to finish the two-hitter.

"That's as good a game as we've pitched all year," Girardi said. The shutout was the third for the Marlins, who improved to 10-19 in one-run games.

Cody Ross produced the only run off Ramon Ortiz (6-9) in the second inning with a two-out home run, his fifth.

"When Cody hit the home run I thought, I've got to keep them scoreless," Sanchez said.

Washington went 0-for-8 with runners in scoring position, stranding three at third base.

"Opportunities -- we can't take advantage of them," manager Frank Robinson said. "How many times have we said that? We're a major league ballclub, and we can't get people in from third?"

Sanchez walked the first two batters in the fifth, but Brian Schneider grounded into a double play and Ortiz struck out.

"Anibal has shown he's got some poise," catcher Matt Treanor said. "He'll make some bad pitches and then regroup."

Sanchez, who threw 106 pitches on an 89-degree afternoon, departed after walking Kearns to start the eighth. Taylor Tankersley came on and struck out Felipe Lopez with two on to end the inning.

Ortiz lost his third start in a row despite limiting Florida to six hits in seven innings.

"Nothing's going good for us," he said. "It's unbelievable. It's a crazy game, man."

Starters are winless in the past 12 games for the last-place Nationals.

Notes

• The Nationals returned home after the game, but RF Jose Guillen remained in Miami for further examination of his sore right elbow, Robinson said. Guillen has been bothered by the injury this month and left Tuesday's game in the third inning. 2B Jose Vidro (left hamstring) missed his second consecutive game Wednesday, and his status is day to day.
• With several thousand children in the stands for the 1:05 p.m. ET start on Camp Day, announced attendance was 25,546, Florida's fourth-largest of the season, although the actual crowd was about half that.