He sent Julius Randle into the game at center and Josh Hart in at shooting guard, and the small lineup helped erase a 19-point deficit before Kentavious Caldwell-Pope provided the knockout punch down the stretch in Los Angeles' 103-94 victory at Staples Center.
"It took Julius and Josh Hart getting put in the game, two of our tougher players, to really spark the energy level, the effort level," Walton said. "Once we got it, we didn't turn it off."
Caldwell-Pope scored 11 of his 21 points in the closing minutes, Kyle Kuzma scored a game-high 22 points, Brandon Ingram added 17 points, and Jordan Clarkson scored 12 off the bench for Los Angeles (8-10). Hart contributed five points in 15 minutes.
Denzel Valentine shot 5 of 7 from 3-point range and scored 17 points to lead five starters in double figures for the Bulls (3-12).
Antonio Blakeney, on a two-way contract that allows him to split time between the Bulls and their G-League affiliate, the Windy City Bulls, scored 15 off the bench.
The Lakers rallied to tie the score at 80 on a layup by Hart with 9:32 left. Los Angeles went ahead 89-87 when Caldwell-Pope put back a missed 3-pointer with 3:06 remaining.
Caldwell-Pope followed with two 3-pointers that stretched the lead to five each time, and the Lakers kept Chicago from getting back within one possession.
"It is a learning opportunity for the guys to be down 20 and realize you don't need hero shots," Walton said. "You just need to tighten up what we're doing and we can get back in the game."
The Bulls took their biggest lead at 61-42 with 10:29 left in the third quarter. An 8-2 run pulled Los Angeles within 13, but the Lakers couldn't get within single digits until Clarkson replaced Lonzo Ball and joined starters Kuzma and Caldwell-Pope and reserves Randle and Hart.
"They're the key to us coming back," Kuzma said of the reserves. "They came off the bench and gave us a lot of energy, made a lot of plays for us. We probably wouldn't have won without them."
Chicago coach Fred Hoiberg was impressed by one Los Angeles player in particular.
"Julius Randle changed the game for them when he went in there at the 5," Hoiberg said.
The Lakers cut the deficit to one on a 3-pointer by Clarkson with 35 seconds left in the third quarter and then trailed 75-72 entering the fourth.
Behind double-digit first-half scoring efforts from Blakeney (15), Robin Lopez (12) and Valentine (11), the Bulls led by as many as 18 before taking a 56-42 lead into the break.
Kuzma made his first four field-goal attempts and scored 10 points in the first 5:45, but he was replaced by Randle later in the opening quarter. Randle missed all three of his field-goal attempts and committed one of Los Angeles' six turnovers in the first period.
Valentine and Lopez each went 4-for-4 from the field in the opening quarter and combined for 19 of Chicago's 27 points.
Blakeney entered with 4:58 left in the first quarter and scored 15 points in his first eight minutes, including 11 straight for the Bulls during one stretch, helping Chicago to a 41-26 lead.
Lauri Markkanen, who came in averaging a team-high 15.6 points for the Bulls, was held to three in the first half before finishing with 13 points and 14 rebounds.
NOTES: Lakers PG Lonzo Ball recorded eight points, 13 rebounds and four assists. He shot 3 of 13 from the field, including 2 of 8 from 3-point range. ... The Lakers came in last in the NBA in 3-point shooting percentage at 29.4 percent, and they shot 32.5 percent from beyond the arc. ... Chicago PG Kris Dunn made his second start of the season, replacing Jerian Grant. Dunn finished with 12 points and six assists. ... Chicago SF Denzel Valentine is 15 of 27 from 3-point distance in his past four games. .... The Bulls came in shooting the lowest percentage in the league at 41.4 percent. They shot 38.3 percent against the Lakers. ... Chicago also came in as the second-lowest scoring team in the NBA (95.5 points per game). ... Bulls C Robin Lopez entered with an 8.8 career scoring average, and his twin brother, Lakers C Brook Lopez, came in with an 18.5 career scoring average. Robin outscored Brook 14-4.