WASHINGTON - Rafael Soriano has been so successful closing games for Washington that his teammates want to follow his lead, right down to the untucked jersey.

Soriano converted his 12th save in 13 chances to end the Nationals' 5-4 win over the Detroit Tigers on Thursday to complete a two-game sweep of the AL champions.

Once Soriano retired Prince Fielder on a game-ending flyout to the center field warning track with a man on, Soriano was joined in his signature celebration - untucking his jersey - by several teammates.

"I never thought I would be a guy to do it," first baseman Adam LaRoche said. "But when you've got a teammate out there doing it, I think it's cool for the guys to join in. If that's his thing, great. He's not showing anybody up. It's just his style."

What does it represent to the team?

"No clue," LaRoche said.

Perhaps the gesture's an ode to a bullpen that helped the Nationals claim their first four-game winning streak of the year.

Ryan Mattheus, Drew Storen and Soriano combined for shutout relief after Dan Haren nearly squandered a four-run lead. Washington's three relievers had identical lines, each giving up a hit and striking out a batter in an inning.

LaRoche singled in the first and second innings for his first consecutive multihit games this season, and Ryan Zimmerman, in a 2-for-14 slide coming in, had three hits.

Tigers pitcher Doug Fister (4-1) had an RBI single in the second off Haren (4-3), but the Nationals made it 5-1 in the bottom half on consecutive run-scoring singles by Zimmerman and LaRoche.

LaRoche has eight hits in his last 14 at-bats, raising his average from .129 through May 1 to .196.

"I like where he's at," Nationals manager Davey Johnson said before the game. "I think he's seeing the ball better. His timing's coming around."

Haren allowed four runs and nine hits in six innings, giving up a three-run homer in the sixth to Matt Tuiasosopo.