Villanueva has scored 96 points in the four games since Redd, the team's scoring leader, tore the ACL and MCL in his left knee last Saturday against Sacramento.
Richard Jefferson and Ramon Sessions each had 20 for the Bucks who won their fourth in a row over the Hawks at home. Villanueva was 8-of-15 from the floor, including four-of-seven from 3-point range, in 42 minutes.
"It was a big game for me," he said. "I played a lot of minutes in yesterday's win. I just tried to follow up on that. I just got to keep it up and keep playing with the energy I have been playing with."
Friday, Villanueva had 26 points and 13 rebounds in 41 minutes as the Bucks beat the Toronto Raptors 96-85 for their first win without Redd.
"Coach has put a lot of responsibility on me to go out there and play big minutes and make the most out of it," Villanueva said of the direction he's gotten from head coach Scott Skiles.
Villanueva had eight points in the first, 10 in the second, including a 3-pointer that gave Milwaukee its biggest lead at 49-31, and seven in the third. He played the entire fourth, but only had two free throws.
The Bucks blew that double-digit lead as the Hawks kept chipping away and finally cut it to five just before the half.
Milwaukee re-established itself in the third behind nine points from Sessions, eight from Jefferson and seven from Villanueva.
Mike Bibby led Atlanta with 24 points and Joe Johnson, picked as a reserve to the Eastern Conference All-Star team for the third consecutive season, scored 22, including the 10,000th of his career. But the Hawks failed to snap a three-game losing streak in Milwaukee. Josh Smith scored 18 points and grabbed 11 rebounds while Flip Murray came scored 18.
On Friday, Johnson scored 29 points in Atlanta's 105-88 victory over New Jersey which gave him 9,999 in his eighth year in the NBA.
Bucks center Andrew Bogut played in his second consecutive game since missing eight with lower back spasms. He had nine points and six rebounds as head coach Scott Skiles limited him to 20 minutes or less.
Bogut matched up against Zaza Pachulia.
"He was huge," Hawks head coach Mike Woodson said of Bogut's play in the paint. "He's a big target. Zaza had his hands full."
Milwaukee improved to 17-2 at home against the Hawks since the 1998-99 season.
Sessions' layup gave the Bucks a 106-98 lead with 1:10 left. The Hawks didn't quit as Johnson, Marvin Williams and Josh Smith each had two points to make it 106-104 with seven seconds left.
Luke Ridnour and Jefferson each made a pair of free throws to keep Milwaukee ahead. Bibby hit a 3 at the buzzer.
"They came out and played hard, a lot harder than we did tonight," Williams said
The Hawks trimmed Milwaukee's 14-point lead down to 97-92 when Murray capped a 16-7 run with a wide-open 3-pointer from the corner with 4:14 left. He had eight points during the burst.
Bogut came in late in the third with the Bucks ahead 76-69. He scored four points and had two steals and an assist in a 11-5 run that gave Milwaukee an 87-74 lead heading into the final quarter.
The Bucks built a big lead, but the Hawks fought back before the half.
Charlie Bell, who had 16 points, and Villanueva each scored seven points during a 20-2 tear that gave Milwaukee a 40-22 lead with 8:04 left in the second. But the momentum quickly switched to the Hawks. The Bucks made just four field goals while Murray sparked a 17-2 run with six points and Smith added six as Atlanta got to 53-48 at the half.
Bell sank a shot from near half court to end the first quarter. ... Hawks C Al Horford missed his 12th straight game with a bone bruise in his right knee. Atlanta is (6-6) during his absence. ... The Bucks, who finished January 9-9, led the NBA with five back-to-backs during the month.