WASHINGTON -- The Florida Marlins aren't shocked by their fast start.

"You don't hear anybody saying 'We're in first place,"' catcher Matt Treanor said after Florida routed the Washington Nationals 11-0 on Saturday night for their sixth straight win. "We're not surprised at all."

Dan Uggla drove in five runs and Andrew Miller allowed two hits in seven innings for the NL East-leading Marlins (22-14), who are eight games over .500 for the first time since Sept. 18, 2005. Their winning streak is their longest since they won nine in a row from Aug. 20-29, 2005.

"We're playing good baseball," manager Fredi Gonzalez said. "Hopefully it continues for a long time."

Florida chased Mike O'Connor (1-1) -- making his first start since Sept. 28, 2006 -- during a seven-run fourth inning highlighted by Uggla's second career grand slam.

Miller (3-2) gave up singles in the first to Cristian Guzman and sixth to Felipe Lopez. He struck out seven and walked one. He equaled career highs in innings pitched and strikeouts in winning his third straight decision.

"I think we're pretty good," Miller said. "All the guys in here think we're pretty good. I think we're pretty balanced -- especially if the starting pitcher keeps it up. I pitched pretty poorly early in the year."

Taylor Tankersley worked the eighth and Matt Lindstrom got three outs to complete the three-hitter.

O'Connor's woes started on his very first pitch when Cody Ross drilled his second home run of the year deep into the left-field stands.

"It's good to get on them early and give Andrew some run support," Ross said. "That's all he needed -- just one."

The Marlins scored two runs in the third. Ross scored on a wild pitch and Uggla hit a sacrifice fly to drive in Hanley Ramirez, who is close to finalizing a new contract with the team.

Wes Helms led off Florida's big fourth with his second home run of the year to make it 4-0. Jeremy Hermida singled in a run, Ross scored on reliever Joel Hanrahan's wild pitch and Uggla went deep for his ninth homer of the season.

"After the second inning I felt like I was on track," O'Connor said. "I went up for the fourth inning and I just kind of lost it."

O'Connor gave up nine runs and walked six in 3 1/3 innings.

"Not a very pretty outing," Washington manager Manny Acta said. "He just didn't have it. Just a very poor start."

Hermida also had an RBI single in the eighth.

Notes

• Marlins OF Josh Willingham, on the 15-day disabled list with a strained lower back, will begin a rehab assignment in the next few days, Gonzalez said.
• 1B Mike Jacobs missed his third straight game with a strained left quad. Gonzalez said he might play Sunday.
• Marlins OF Luis Gonzalez hit the 575th double of his career -- good for 18th place on the career doubles list.
• Nationals 1B Dmitri Young, who's been out since early April with a back injury, will start a rehab assignment early next week at Double-A Harrisburg, general manager Jim Bowden said.