Later, Williams showed that if the Cardinals are going to motor on to Detroit for the Final Four, he's got to be their engine.
Siena had the tournament's overall top seed sweating in the second half. The Saints went on a 12-0 run that Rick Pitino couldn't stop despite calling three timeouts. Louisville found itself trailing 63-59 with a little more than seven minutes left, its season in the balance.
Williams finally put an end to the run, first with an offensive putback and then with a 3-pointer from the corner that lifted the Cardinals back ahead. He capped his team's bounce-back 9-0 spurt by speeding to the rim, up-faking and laying the ball in for a 68-63 lead. As Siena called timeout, Williams sprinted to half court and pounded his chest.
"He found that extra gear, and if he doesn't our season is going to be over and we're going to go home," Louisville guard Andre McGee said. "That's a gear I don't know how many clutch automobiles have. Few people have it. And luckily, he had it for us."
Williams continues to do a little bit of everything for the Cardinals. He finished with 24 points, 15 rebounds, four assists and two steals in 38 pressure-charged minutes. He blocked away a Saints lob attempt, came over to say hi to Verne Lundquist at one point and even grabbed a camera to take a picture of himself when he fell into the photographers' row. Before the post-game press conference began, he assembled the placards in front of him and teammate Earl Clark.
Still, Williams' most impressive stat might be his numbers from the 3-point line, where he drilled four of six. He came into his this season as just a 30 percent career shooter from beyond the arc and had suffered some wretched days with his jumper. Early on this year, though, Pitino worked with him to change the form on his shot, keeping Williams' elbow tucked in under the ball.
Williams, who's always had one of the quickest first steps around, agreed to the change after getting some advice from Darrell Griffith, the star of Louisville's 1980 NCAA championship team.
"He told me, 'A jump shot will set you free,'" Williams said.
This season, Williams is shooting a career-best 38.4 percent from the arc, inspiring confidence instead of shudders when he rises up from long range. Defenders can no longer just slack off him when he's 20 feet away from the goal.
"If someone had come to me when I'm 22 years old and told me I've got to change my shot at this stage of my career, I'm really not going to listen to that," McGee said. "But he trusted Coach, and it's been working for him this year. I'm proud of him for taking that risk."
Louisville faced the very real risk of becoming the first No. 1 seed to lose, thanks to a fearless effort by the Saints.
Point guard Ronald Moore sliced through the full-court press and had 10 assists and only two turnovers. Siena had only five turnovers when it grabbed the 63-59 lead. The Cardinals were the ones fumbling it away, on their way to 17 miscues for the game.
"We thought we had 'em," Saints guard Kenny Hasbrouck said. "We were running them up and down. We kept up with them every time."
Pitino told his players in one of the three timeouts that their season was about to end if they didn't turn things around. The pressure caused four turnovers in the final seven minutes, and Louisville controlled just about every rebound.
That response told Pitino something he didn't know about his team.
"People asked me how good we were," he said. "And I never really could answer it honestly until we were down four, and we had to make big plays offensively and had to make big rebounds defensively. Not until that point did I ever believe that this team had it.
"They tried hard, and I always gave them the confidence that I believe in them, but I never felt it. At that point the No. 1-ranked team was ready to go down, calls weren't going, they think, in their favor. They had to really make big plays. And they did."
Now the Cardinals are moving on to another city that knows a little something about motors: Indianapolis, where 12th-seeded Arizona awaits in the Sweet 16. Two more wins will get them to Motown. Williams will have to be their driver.
"He's our leader, and he's a great player," Clark said. "You all saw it out there today with his shooting ability and rebounding. When we needed big shots, he delivered."