MIAMI -- The Cubs' road winning streak is alive again -- and just in time for them to go home.

Alfonso Soriano and Aramis Ramirez each hit two-run doubles, and Reed Johnson smacked a bases-clearing double to highlight an eight-run seventh inning and lift the Cubs to a 9-2 victory Sunday over the Florida Marlins.

Chicago won five of six games on this trip to Atlanta and Miami, and has won 10 of its last 11 games on the road. More importantly, the Cubs won their sixth straight series, and will leave Florida before Tropical Storm Fay hits.

"It was a real nice road trip," Cubs manager Lou Piniella said. "You have to be pleased."

Ryan Dempster (14-5) survived sweltering 92-degree heat to strike out 10 over six innings for his 10th double-digit strikeout game, and third this season. He's now one "W" shy of his career best and tops on the team in wins. Could he have imagined this season would go so well?

"I dreamt about it," Dempster said. "You work really hard and hopefully you get the results. But you go about it the right way through executing pitches one at a time, and try to find yourself in a good position. I feel good. I feel strong. I think that's what enabled me to get through that one inning, the sixth inning. I was up near 100 pitches and felt I was strong enough to make the pitches I needed to make."

He walked Hanley Ramirez to open the sixth, then gave up an RBI double to Luis Gonzalez to give the Marlins a 2-0 lead. Jorge Cantu singled, but Dempster regrouped and struck out the next two batters, then intentionally walked Jeremy Hermida, and got Cody Ross to fly out.

For the game, Dempster gave up two runs on five hits.

"His stuff is as good right now as it was early in the year, and that's saying a lot," Piniella said of the right-hander. "It shows how good a shape he is in and how hard he works. And he's got the mental toughness."

Ask Dempster, and he'll tell you he's pitching better now than he was earlier this season.

"I feel that sometimes I'm getting away with pitches that I wasn't getting away with then," Dempster said. "My fastball has good life on it, and my slider and split are both pitches I'm able to throw for strikes, and strike guys out with.

"I just try to be consistent and work hard between starts. It's easy to sit in your chair and puff your chest out and enjoy the success and not continue to work hard. Ultimately, it comes down to your next start and what are you going to do then. I'll enjoy this one, and we'll enjoy it as a team, but I've got to get back on the horse and ready to go next time."

Dempster's name isn't mentioned much in discussion about National League Cy Young candidates. That could change in the final six weeks of the season.

"He puts a couple more wins on the board quickly, and I think you'll start hearing a few whispers," Piniella said.

"There's a lot more guys ahead of me," Dempster said. "I just worry about making my starts. I figure if every fifth day I'm ready to pitch, at the end of the year, those things play themselves out."

The Cubs stranded 13 baserunners on Saturday in a 2-1 loss to the Marlins, and appeared to be in the same funk Sunday, leaving six on in the first four innings. Then came the seventh.

Mike Fontenot doubled to lead off and Johnson singled to chase starter Chris Volstad. Renyel Pinto (2-5) walked pinch-hitter Mark DeRosa, and Soriano doubled to left past a diving Gonzalez in left to tie the game at 2.

One out later, Derrek Lee was intentionally walked to load the bases and Ramirez smacked a two-run double past Cantu at third. After Kosuke Fukudome hit a sacrifice fly, Pinto intentionally walked Geovany Soto and was pulled. Logan Kensing unintentionally walked Ronny Cedeno to load the bases, and Johnson's double cleared them.

"We had some runners on base early in the game, and we weren't able to capitalize," Johnson said. "Give credit to the guys who were able to hit with runners on base."

The Cubs tied a season high with six doubles, went 5-for-14 with runners in scoring position, and still stranded 10.

"They say hitting is contagious, and that's what happened there in the seventh inning," Johnson said. "Guys just started rolling."

Ramirez, back after missing three games because of a bruised hip, finished the road trip 8-for-15 with eight RBIs. Johnson had his second four-hit game of the season, which matched a career high, and ended the trip 9-for-18 with four RBIs.

Dempster could've been the losing pitcher Sunday, and was lifted for a pinch-hitter in the seventh.

"That's all we had to do was get me out of the lineup," he said jokingly.

It paid off.

"He's got a pretty good year going," Piniella said of the right-hander. "He's just got to finish it off. The way he's throwing, there's no reason he won't."