Neither the partisan crowd at the Edward Jones Dome nor his players were so reserved, but while time remains on the clock Self is all business. Until that buzzer sounds, his expressions of emotion are usually reserved for disbelief, outrage or some combination of the two - an unfortunate official or team member on the wrong end of a verbal shotgun.
So that smile spoke volumes. The win was coming, a victory over top-seeded North Carolina and a trip to the Final Four. And man, did it feel good.
It's not so hard to understand Self's joy. Five months ago, was there a soul in the college basketball world who believed something like this was possible? Beat writers, columnists and talking heads all agreed - this was the year Kansas would truly enter rebuilding mode for the first time during Self's tenure.
Not even the fans seemed to disagree. Making the NCAA Tournament was expected, of course - this is still Kansas after all - but even the most fanatical among Jayhawk Nation found it difficult to believe this team would challenge for an eighth consecutive Big 12 Championship and once again stamp a place for itself among the nation's elite.
Their reasoning was based in issues of personnel - issues not without merit. On paper, the Kansas roster was as thin as any in recent memory. The one seemingly surefire star, Thomas Robinson, averaged less than 15 minutes a game a year ago.
The Jayhawks appeared to be short not only on experience, but on talent and depth. Which, as one might be able to deduce, isn't a great recipe for success.
But Travis Releford can pinpoint the exact moment he and the rest of the players whose names populate that roster began to believe this group was capable of something special.
"The beginning," the junior small forward said. "Coach probably didn't agree with it, but we all came together outside of the gym and just was talking, and told ourselves that we're (going to come) together this year and listen to coach and listen to the things he wants us to do and play the way he wants us to play. Then, we can get there."
Hindsight is a wonderful gift. With it, one can now see clearly that everyone outside the locker room at Allen Fieldhouse failed to take one very critical factor into account when evaluating this team.
They have "it."
"It" is an ambiguous term that refers to an equally ambiguous quality. What is it? How does one get it? Nobody knows what it is, exactly - well, nobody except ESPN analyst Jimmy Dykes - but they know it when they see it.
For the 2011-2012 Jayhawks, "it" has been a number of things. It has been an unshakable self-confidence, even in the face of all that public doubt and some early-season stumbles. It has been the ability to stare down tension-packed late-game situations without blinking.
At no point was this quality more perfectly on display than in the second half of Sunday's win over the Tar Heels; to compress it even further, the final three minutes.
With 3:09 left in the game, the attitude started to change. The Jayhawks had maintained the lead for the previous eight minutes, but it was tenuous at best. The Tar Heels would close the gap and surge to within a point, and Kansas would find a way to buy themselves another sliver of breathing room. There was a sense they could only keep it up for so long.
The Jayhawks had to find a way to put them away for good, and that's when Elijah Johnson saw his opening. Slipping a defender he rose up and cut loose with a deep three pointer - the kind he's developed a penchant for hitting in clutch situations - and watched coolly as it splashed through the net.
"I wouldn't want to go home tonight saying I could have shot that three that he backed off of me on," Johnson said. "He took a step backwards and I made him pay for it. I pulled up. I keep finding myself in these situations where in a late game I'm taking that shot."
That shot was the turning point in what was a magnificent stretch of basketball for Kansas. With approximately nine minutes remaining, Self made the switch to a triangle-and-two defense - sticking men on North Carolina's perimeter scorers Harrison Barnes and Reggie Bullock and zoning the lane.
It so flummoxed the Tar Heels that they failed to register a field goal during the final 5:43 of play, and the Jayhawks took advantage. Spurred on by great defensive plays - specifically two huge blocks by Jeff Withey and some great rebounding - Kansas poured it on.
Tyshawn Taylor made a layup and was fouled. Releford pulled down a rebound, passed it to Taylor and sprinted ahead of the pack for an easy dunk on the other end. And the whole team hit its free throws.
Before anyone could blink, the margin was 13, the game all but over, and there was Self, smiling quietly on the sidelines.
In the storied history of Kansas basketball, this team is unique. Self took raw material nobody believed to be exceptional, and from it carved a masterpiece. A tough, hard-nosed, defensive-minded masterpiece that takes nobody for granted and believes it can play with anyone, even when nobody else does. Maybe especially when nobody else does.
Self has coached a lot of great teams during his career, including a national champion. But he recognizes that this team is different. It's not his most talented. It's not his best defensive team, or his most athletic or his most skilled. But it's the one which has come the closest to maximizing its potential and leaving everything out on the court.
And as it turns out, when those inside the locker room believe, that counts for an awful lot.
"I will say this," Self said. "I don't know if I ever enjoyed coaching a team more than this one. I love them. We fight, it's combative sometimes, all those things."
"But I love coaching these guys."