"What a great prediction that was," Stevens said Wednesday night. "Pretty obvious when you see him now. But he was a 6-7, gangly kid that was a great tennis player."
Hayward, too, is a believer in Stevens' abilities, though he never made the same prediction for his old college coach.
Earlier this year, Stevens and Hayward went out to eat and talked about Butler basketball. Who would score? Who would bang in the post?
A month later, Stevens made the leap from college to the pros, taking the reins of the Boston Celtics. So on Wednesday night at T.D. Garden, the two men most synonymous with the Bulldogs' run to the 2010 national title game, faced off against each other.
"When I go out there and see him in that green and see him on the opposing side, that's when it will hit me," Hayward said as he spoke with reporters before the game.
Both men are convinced the other will succeed at the highest level.
Hayward lauded Stevens' game preparation and his calm demeanor.
Stevens said Hayward has "really gotten better since I coached him."
The coach reflected back on the time he watched Hayward play a high school tennis match, dressed in a Purdue hat and Purdue shorts. It turned out to be the only regular-season loss for Hayward.
Even after Hayward committed to Butler to play basketball, his focus was on tennis and winning a state championship.
"But you saw the physical tools. You know the mental side of things is high-level," Stevens said. "Then it was a matter of, 'Once he starts committing himself to basketball full time, how good can he get?' Question answered."
Stevens watched as Hayward's game improved and his body developed. He could bench-press 185 pounds three times when he first arrived at Butler. Fifteen months later, he was doing it 14 times.
Stevens helped mold Hayward at Butler, culminating with a half-court heave that came agonizingly close to glory. Stevens, though, said he "hardly ever" thinks of Hayward's miss at the end of the NCAA championship game against Duke.
"I felt bad for him because the immortalized shot of his bangs off the rim," he said. "The one they show every single year in March. The only reason I think about it is because they show it on TV."
Now, Stevens is watching film of his former pupil. As he watched this week, he felt joy and pride as he examined Hayward game.
"Then you get sick to your stomach," he said, "because you've got to play against him."
After Brandon Rush made his Utah Jazz debut Tuesday night, his first action in more than a year since tearing his anterior cruciate ligament last November, coach Ty Corbin said he would rest the guard in Boston, the second night of a back-to-back.