Ball was coming off a 3-of-18 shooting performance in a game that had play-in implications for New Orleans. It was one of the worst shooting nights of his NBA career.
Williamson said Ball told him: "I'll be there tomorrow."
"Those were big words," Williamson said.
Ball responded to his off night by tying his career high with 33 points, hitting a clutch step-back, 18-foot jumper to put New Orleans ahead for good with 25.3 seconds to play and knocking down four free throws after that to lift the Pelicans to a 108-103 win over the Warriors on Tuesday night.
It was the second time in three games Ball has hit his career high in points; he set the mark in a win against the Minnesota Timberwolves on Saturday. But in between those two 33-point efforts was a clunker of a shooting night, something that weighed on him after the final buzzer sounded.
"I just knew I let my team down and I wasn't gonna do that two nights in a row," Ball said about sending the text to Williamson. "I know the type of player I am and I believe in myself. I knew I wasn't gonna shoot 3-of-18 again. I just wanted to let Z know I was gonna be there with him tonight.
"I know what I can do on the court and I didn't step up to the plate last game. I wanted to be there for the guys tonight, especially Zion. He's going out every night basically getting 30 and 10 for us. For me to have the type of performance I had yesterday is pretty unacceptable, especially at this time of the year. I wanted to fix it."
Ball had 11 points and knocked down three of his four 3-point attempts in the first quarter. He finished strong, as well, with 12 points in the fourth quarter, the third most he's ever had in the final period, according to ESPN Stats & Information research.
All 12 of his fourth-quarter points came in the final 3:18. He hit a pair of 3-pointers to tie the game -- at 95 with 3:18 left and at 98 with 2:13 to go -- before hitting the step-back jumper for the lead. He added four free throws late to improve his season percentage at the line to 80.0% -- a big step for someone who shot 41.7% from there just two seasons ago while with the Los Angeles Lakers.
"He went up there with so much confidence and just knocked down free throws," Pelicans coach Stan Van Gundy said. "He's worked on that. And when you work on something that much and get good at it, you're going to have great confidence."
Williamson said he had "a lot of respect" for Ball sending the text message and coming out and backing it up with his play Tuesday.
"I'm glad he's my teammate," Williamson said. "You love to have teammates like that can say stuff like that and come the next day and show out. He just wants to win. That's what I love about Lonzo. He just wants to win. And he'll do whatever it takes to win."
After Ball put the Pelicans up two late, Williamson came up with one of the biggest plays of the night. Stephen Curry's 3-point attempt to answer Ball's shot was off target, and Warriors guard Mychal Mulder came up with the rebound. But Williamson tipped it away and got the steal around the center-court logo and dribbled into Draymond Green, who took a foul that was deemed clear path, since Ball was breaking away for a layup on the other side of the court.
Williamson knocked down his two free throws, and Ball later hit his, as well, to stretch the lead to six with 14.6 seconds left.
"That loose ball was a winning basketball play," Van Gundy said. "That's what we talked about today. Over these last seven games, counting tonight, we want to focus on playing winning basketball. We talked about taking care of the ball. Only 12 turnovers tonight. We talked about our defensive commitment. We talked about getting back, which was a lot better tonight. We didn't necessarily play pretty basketball, but we made more winning plays tonight than we did last night."
Some of those winning plays came without the help of Pelicans forward Brandon Ingram, who suffered a left ankle sprain just before halftime. Ingram played until the 4:39 mark of the third quarter before exiting for good.
The Pelicans said on Wednesday that Ingram will miss Friday's game against the Philadelphia 76ers and he's day-to-day.
The win kept the Pelicans alive in the hunt for the play-in tournament in the Western Conference. New Orleans improved to 30-36 and sits two games behind the San Antonio Spurs (31-33). San Antonio owns the tiebreaker over the Pelicans after winning the season series 2-1.
Both teams have difficult roads the rest of the way. New Orleans has a five-game road trip starting Friday against the 76ers before facing Charlotte, Memphis, Dallas and Golden State. The Pelicans finish the season May 16 against the Lakers in their final home game of the season.
San Antonio has the toughest remaining schedule with upcoming road games against Utah, Sacramento and Portland before one home game against Milwaukee followed by two road games against Brooklyn and New York. The Spurs finish the season with a back-to-back at home against the Phoenix Suns, who could still be competing for the top seed in the West.