Here was Green, a first-year head coach, battling it out adjustment for adjustment with Ty Lue, a championship-winning coach considered by some to be among the best in the league. The heavyweight fight, as Green called the battle, was tilting in Lue and the Clippers' direction when New Orleans watched a 16-point first-half lead evaporate into a 10-point Clippers lead by the end of the third quarter.
But when he and his team needed it most, Green and the Pelicans landed haymaker after haymaker with Jonas Valanciunas landing the final knockout blow with 12.6 seconds to go, dunking it home and giving the Pelicans a come-from-behind 105-101 victory.
New Orleans advances from the play-in tournament as the No. 8 seed to face the top-seeded Phoenix Suns. Their first-round series begins Sunday night.
The Pelicans become just the fourth team in NBA history to start a season 1-12 or worse and make the playoffs, joining the 1996-97 Suns (0-13), the 1984-85 Cleveland Cavaliers (1-12) and the 1967-68 Chicago Bulls (1-12), according to ESPN Stats and Information research.
The Pelicans led by 10 at halftime but that quickly turned the Clippers' way as they used a 34-6 run over the final minute of the second quarter and into the third quarter to swing momentum their way.
Los Angeles came out slow after learning that seven-time All-Star Paul George was placed into health and safety protocols earlier in the day. The Clippers were already without Kawhi Leonard, who didn't play a game this year at all.
"He was making adjustments," Green said. "He took his bigs out. We were trying to adjust to them. It didn't work for us. We put our bigs back in. That didn't work for us either.
"So we were throwing darts at the dartboard trying to figure it out how could we find an environment that we can play in on both ends of the floor."
Eventually, Green landed on a lineup with Brandon Ingram, CJ McCollum, Larry Nance Jr., Trey Murphy and Herb Jones playing most of the minutes down the stretch. It gave New Orleans a switchable lineup on defense with enough shot-making to get things going offensively.
Part of what got the Pelicans going in the fourth quarter was a fiery speech by Green, something that Murphy said caught him off guard.
"It was a different side of Willie that I haven't seen, in all honesty. He got really fired up," Murphy said. "Most of the time he's very even-keeled, but he got really fired up and lit into us. I think that sparked us in that fourth quarter. At the end of the day, we didn't want our season to be over. We wanted to keep playing, and he definitely spearheaded that."
After the Clippers got off the first punches of the first quarter, the Pelicans answered back with a 27-7 run that gave them a 101-94 lead with 2:10 to go, completed by Murphy's fourth 3-pointer of the night.
"Guys stepped up," Ingram said. "Trey Murphy was big in that fourth quarter. Defensive rebounding and knocking down shots. We're going to need that from him as we go on. ... Larry Nance came in and was really, really good on the glass. We needed something from everybody today."
It was Ingram who got the Pelicans going early, scoring 16 of his game-high 30 points in the first quarter. Green said Ingram had been locked in since the team left New Orleans.
"Brandon Ingram is the truth," Green said. "He just brought it. He had that look in his eye from the time we got on the plane. Shootaround, he's been locked in. He has been waiting for this moment, for this type of moment."
Green also credited Nance who came off the bench with 14 points and 16 rebounds, including the dunk that put New Orleans up for good with 4:02 to play.
"Larry was a monster," Green said. "We kind of figured it was going to be a Larry game, the way they play. Ty Lue's adjustments was to go small and Larry has the ability to guard a number of perimeter guys. He's big, he's strong, he can rebound the ball. We don't win that game without his effort."
It's the first time Ingram has made it to the playoffs in his NBA career, something he said he's excited for. McCollum, whom the Pelicans brought over in a midseason trade, has never missed the playoffs in his nine-year career after making eight in a row with Portland.
McCollum said he's glad his teammate gets to join him in the postseason.
"He's one of them ones," McCollum said of Ingram. "He's a special player. He gets to his spots. Obviously I play alongside him and I'm happy about that but I'm glad the world gets to see who he truly is. I think sometimes if you don't make the playoffs, people kind of forget about you or underestimate your talent. Now he gets to play on the biggest stage. He showed tonight how great he is."
For the Clippers, Friday night marked a disappointing end to a season filled with what-ifs due to the extended absences of their two stars. George missed 52 games this season, including Friday's play-in, with the Clippers going 24-28 in his absence and 18-14 with him in the lineup. Leonard remains out as he rehabs a torn ACL, and the team said there is still no timetable for his return.
Lue said he thinks the Clippers can be a force next season with a healthy George and Leonard.
"We get our main guys back," Lue said. "I mean, we can be dangerous. Health is part of it. We got to stay healthy, continue to work."
Lue added: "When you get Kawhi back, top-five player, PG, a perennial All-Star, your team changes tremendously. Guys who have taken on bigger roles this year who have never been in this position before, they can kind of fall back into their original roles. We could be very different with those two guys back and healthy. ... We can be special."
ESPN's Ohm Youngmisuk contributed to this report.