At just the right time, too, since Lacy's bullish running style seems well suited for bad weather in December.
Green Bay (9-4) has a one-game lead in the NFC North over Minnesota after its second straight victory following a 1-4 slide.
''We all make a couple bad decisions along the way and that doesn't change my opinion of Eddie,'' McCarthy said. ''So he needed to refocus and he did that.''
Lacy hoped this was a springboard for the stretch run.
With 435 yards and 29 first downs, the Packers got better balance and production out of an offense that still struggled at times with penalties and short-yardage situations. The defense and running game came up with big plays in the fourth quarter.
Aaron Rodgers threw for 218 yards and two scores, though all the Packers really needed from their star quarterback late in the game was to hand off the ball. Lacy and Starks each had touchdown runs in the fourth quarter on a rainy night.
''He's a big, strong, powerful runner,'' Rodgers said about Lacy. ''The ball's a little slick at times and we need him to keep the chains moving.''
With the loss, the potential for a .500 record slipped away from the Cowboys (4-9). Their chances in the mediocre NFC East took a hit, too.
Dallas fell two games back of divisional leaders Washington and Philadelphia, who both won on Sunday.
''I think we were all looking at what was happening with the other ballgames and were full of `What if' and promises,'' Cowboys owner Jerry Jones said. ''That game was sobering.''
Other notes and takeaways from Sunday's game:
MAKE THE CALL: The biggest change for the Packers this week was McCarthy taking back play-calling responsibility from associate head coach Tom Clements. He called it a tough personal decision to make with a long-time assistant, but something he needed to do professionally.
Instead of suggesting plays to Clements, as he had the past four weeks, it was now Clements suggesting plays to McCarthy.
''But I don't think it's been about the play-calling,'' Rodgers said. ''It's been about the execution. We haven't executed really well. Today was a little better.''
LOSING CAUSE: The Cowboys clinched their first losing season under coach Jason Garrett, who took over when the team was 1-7 in 2010.
They had three straight years finishing 8-8 before going 12-4 last season.
But the passing game struggled. Matt Cassel, starting his sixth game for the injured Tony Romo, was 13 of 29 for 114 yards. Green Bay's Sam Shields had an interception in the end zone on a pass that deflected off Dez Bryant's hands in the first quarter.
REVERSAL RERUN: Bryant was held to one catch for 9 yards. He had a long reception in the second quarter overturned on replay - the same thing happened to him last season during the Cowboys' loss to the Packers in an NFC divisional round playoff game.
The latest reversal wasn't as big a deal to Bryant.
''It is what it is, man. When they called it incomplete, it was incomplete,'' Bryant said.
GETTING DEFENSIVE: The Packers allowed runs of 50 and 45 yards to McFadden, and got gashed on the ground on the drive that led to Turbin's score.
Otherwise, it was a good day for coordinator Dom Capers' unit. Clay Matthews had a sack, plus a hurry in the first quarter that led to Shields' interception.
Shields left the game with a concussion in the second quarter, but the Packers still contained Bryant with rookie Damarious Randall assuming the assignment. Another rookie, cornerback Quinten Rollins, also took on a larger role.
''That's why we drafted guys like those two, to be able to come in and fill the void, especially when a starter like Sam goes down,'' Matthews said. ''Just a great job being ready.''
AP NFL website: www.pro32.ap.org and www.twitter.com/AP-NFL
Follow Genaro Armas at http://twitter.com/GArmasAP