In a frantic finish, Gregg worked out of a jam by getting Paul Lo Duca to bounce into a game-ending double play, preserving a 4-3 Marlins win in front of 24,549 at Nationals Park.

But if not for a well-timed vertical jump by Willingham at the wall in left field, the Nationals may have at least tied the game, and perhaps forced extra innings.

With one out and Lastings Milledge on second after lining a double, Nick Johnson connected on a long drive to deep left. Willingham got to the eight-foot wall in front of the Marlins bullpen, made a leaping effort and nearly hauled in a remarkable catch. Instead, the ball popped out of his glove, and Johnson had an RBI double.

Still, if Willingham hadn't touched the ball, it would have been a homer. In fact, Johnson was in his home run trot as he headed to first.

"I had a 28- to 30-inch vertical right there," Willingham quipped. "We were in a no-doubles [defense] -- the right fielder and center fielder. But I wasn't. I was playing a little deeper. The ball was hit well. I went back on it.

"When I felt myself on the track, basically I just tried to jump. I didn't know the ball was actually going over the fence at the time. I had the ball in my glove, but when my hand was over the fence and it came back, it just kind of jarred it out. Yes, it was over the fence."

From his point of view, Johnson was unsure if he was robbed of a homer.

"I hit it good -- I didn't see it," the Nationals first baseman said. "He made a heck of a play on it."

As it turned out, Willingham's glove saved the game. Because with one out and two on, Gregg got Lo Duca on a split-finger fastball to bounce to second base, getting the game-ending 4-6-3 double play that completed a three-game sweep in Washington, D.C.

"Obviously, [Johnson's ball] was going over the fence, and he made a heck of a play to get up there and keep it in the ballpark," Gregg said. "This is not exactly how you draw it up, but we preserved the win, and we walked away with the victory.

"I got myself into a situation where I needed a double-play ball, and I got it."

By holding on, the Marlins can now chalk up yet another first in this young season.

For the first time the Marlins swept a three-game set in Washington. The last time Florida pulled off a road sweep over the Nationals franchise came on Sept. 27-29, 2004, during its days as the Montreal Expos.

It was also the first time Florida has swept the Nationals since Aug. 21-23, 2006, in Miami.

"I don't care if it is road, home, in the Caribbean, three games are three games," manager Fredi Gonzalez said.

Technically, the Marlins faced the Nationals -- then the Expos -- as a road team in a couple of series in Puerto Rico a few years back.

Marlins starter Mark Hendrickson and Nationals left-hander Odalis Perez each were efficient and effective through five innings.

The Marlins finally got to Perez in the sixth inning, scoring twice with two outs. Hanley Ramirez doubled to open the inning, and he moved to third on Dan Uggla's grounder to second. With the infield in, Jeremy Hermida reached down and ripped an RBI single on a 3-1 pitch.

Perez was lifted after 93 pitches with two outs in the sixth inning. Jorge Cantu put the Marlins in front with a run-scoring double off reliever Saul Rivera. In the eighth inning, Cantu added an RBI single off Luis Ayala.

The Nationals took an early lead on Ronnie Belliard's homer to lead off the third inning.

That was the only run Hendrickson allowed.

"I was reading the hitters very well," said Hendrickson, who felt like he was in a good groove with catcher Matt Treanor. "I just executed pitches when I had to. Even the home run was a pretty good pitch. It was one of those tip your cap to Ronnie. We did well offensively to keep adding on, because obviously, that was a big part of how it [turned] out."

In the eighth inning, the Nationals pulled within a run, capitalizing on a miscommunication in the outfield between Hermida in right and Cody Ross in center. Lo Duca was credited with a double when Hermida pulled away at the last second, feeling that Ross, who was charging all the way, was calling him off the ball. Johnny Estrada's pinch-hit single scored Lo Duca.

The speed of Ramirez provided an insurance run in the ninth. After singling, Ramirez scored from first on Willingham's two-out double to left.

"It's big to give your closer a couple of runs to work with, to breath a little easier, maybe," Willingham said. "You've always got to keep adding runs on, if you can."