The Cowboys led the Rams 24-16 at home last week. They lost 35-30.
They led the Packers 21-12 at halftime Sunday. They no longer lead.
Aaron Rodgers found Jordy Nelson for a 10-yard touchdown with 14:54 remaining, and Mason Crosby made his first extra point after two misses, giving the Packers a 22-21 lead.
The Packers have found something in their run game. After gaining only 35 yards on eight carries in the first half, the Packers have now run for 121 yards.
Aaron Jones, who had 33 rushing yards at halftime, has 16 carries for 104 yards and a touchdown.
Rodgers now is 16-for-21 for 181 yards and two touchdowns. He has completed passes to seven different players.