The Miami newcomer struck out five in four innings and the Miami Marlins tied the Braves 2-all Tuesday. The game was called after 10 innings.
Zambrano gave up two hits and one run.
The last time he faced the Braves was Aug. 12 at Turner Field. Pitching for the Cubs that day, he stormed off the mound after allowing eight runs, including five homers, in 4 1/3 innings. Zambrano then cleaned out his locker and never played for Chicago again.
"Thank God I'm back with kind of the form I had back in the days that I used to be very good. I'm very pleased with the outing," Zambrano said.
Zambrano was perfect over his first three innings. He barely had to move to catch a soft liner by Jose Constanzo that ended the third.
"I don't know if it's me, but he got a little anxious when he has people on base. I'm going to address that," Marlins manager Ozzie Guillen said.
Zambrano threw 49 pitches, 29 for strikes, in his second spring start. His fastball topped out at 97 mph.
"The last couple of years, I think he has been sitting at 88, 92. Today he threw a bunch of 96s, 97. His arm looked really good today," Atlanta's Brian McCann said.
In Zambrano's first spring start, he allowed three runs in 1 1/3 innings against the New York Mets.
"Much better than the last time," Zambrano said.
Left-hander Mike Minor was solid for the Braves. He struck out four and allowed one hit in four scoreless innings.
"He's got good stuff. He has a really good breaking ball. He has life on his fastball. When he has command of all three of his pitches he's pretty tough," said Scott Cousins, who struck out twice against Minor.
Zambrano was originally set to be the fifth starter, but he's in line to take Anibal Sanchez's slot. Sanchez will make his spring debut Wednesday against Tampa Bay after being held back because of tenderness in the back of his throwing shoulder.
Logan Morrison made his exhibition and had an RBI double and a walk as the Marlins' designated hitter. He hopes to play left field Thursday. He has felt nagging soreness in his right knee, which underwent surgery in early December.
Miami's Hanley Ramirez made two nice plays at third base, including a barehanded pickup on Martin Prado's bouncer.
The Marlins led 2-1 in the top of the ninth when Christian Bethancourt homered off Evan Reed with one out.
Outfielder Kyle Jensen, one of the Marlins' top prospects, was hit on the left elbow in the 10th inning by Atlanta's Jason Rice. Jensen was going to have X-rays.