Lee's three-run, eighth-inning double off Florida reliever Rudy Seanez gave the Cubs a 5-2 comeback victory over Lee's former teammates, who fell 2½ games behind in the National League wild-card playoff hunt.
The Cubs also picked up a game on Houston and San Diego. They were a half-game ahead of San Francisco, pending the outcome of its late game with Arizona.
"I can't say it [means] more to beat your old team, because I didn't leave on a bitter note," Lee said. "But it feels good to win because these are big games and they mean a lot."
Ryan Dempster earned his first Cubs victory in relief of Carlos Zambrano and LaTroy Hawkins notched the save with an impressive ninth, striking out the side on nine pitches. Hawkins is the first Cubs pitcher to accomplish that feat since Bruce Sutter did it against Montreal on Sept. 8, 1977.
Former Cubs prospect Dontrelle Willis carried a 2-0 lead into the seventh before Corey Patterson singled with two outs, prompting Florida manager Jack McKeon to bring in Guillermo Mota to face Lee. Opposing hitters were hitless in their last 24 at-bats against Mota, and the Marlins' bullpen is one of the game's most dominant.
"You're never in a hurry to face Mota," Cubs manager Dusty Baker said. "This guy is tough."
After Patterson stole second and Lee walked, Aramis Ramirez singled to bring in the first Cubs run. But the rally ended when Moises Alou was called out on strikes, precipitating another bat-slamming episode by Alou over Gary Darling's strike zone.
Neifi Perez led off the eighth with a pinch-hit infield single and advanced on Alex Gonzalez's throwing error, barely beating the throw to second. Sammy Sosa, who was moved down to the No. 6 slot in the batting order for the first time since 1994, singled on Mota's first pitch to tie the game 2-2 and stifle the boo-birds who have hounded him lately.
"I'm a strong guy," Sosa said. "I'm a survivor for all the things that have happened to me. Sometimes it's going to happen. One thing I know is I have to continue playing. That's the only way you can get out of a jam."
The Cubs loaded the bases with one out when McKeon brought in Seanez to face Lee. After swinging and missing badly on a 3-1 pitch that would have been ball four, Lee lined a slider into left-center field and watched it roll to the wall, clearing the bases for a 5-2 Cubs' lead.
Zambrano pitched seven strong innings but left with the Cubs trailing 2-0. The Marlins blew a chance to rip the game open in the third when Juan Pierre tried to advance from first to third on an infield chopper to Zambrano. Shortstop Nomar Garciaparra alertly directed Zambrano to wheel and throw to third, where he nailed a sliding Pierre for the first out.
"Where the [heck] is Pierre going?" McKeon asked. "In this game you're not outrunning the [darn] ball. I don't [care] if you're Jesse Owens, you aren't going to third on that one. I guess he thought it was going to bounce to the moon. The old cardinal rule is don't make the first or third out at third."
Pierre knew he had made a huge mistake.
"If there's one aspect of the game that was the turning point, it was me running us out of that one inning," he said.
The late-inning victory was a big morale boost for the Cubs.
"We're getting down to where every game is important," Garciaparra said. "I think it's important not to put too much pressure on each other. I think you could see guys pressing a bit when we weren't able to score runs. Sometimes you try to do too much.
"This is something we can build on, where we say, 'Hey, we know we can do it.'"