Kallis announced on Christmas Day that he would bring the curtain down on a glorious 18-year Test career in this week's second Test in Durban.
A fairytale script has since unfolded as Kallis brought up his 45th Test century on day four and, in so doing, passed Rahul Dravid to become the third highest runscorer in the history of the game.
The 38-year-old, who also has the small matter of 292 Test wickets to his name, is set to go out as one of the greats of the game, but admitted his final century would be one he cherished long into retirement.
"It is a special feeling," said Kallis, who hit 115 before top-edging a sweep off Ravindra Jadeja.
"It's strange walking out to bat knowing that there is no tomorrow and it will be your last opportunity to get a 100 for your country.
"It's a different kind of pressure, being in the nineties for the last time was different to normally being in the nineties. At least I could fall back on my experience and managed to get the three figures."
Kallis had come in with the Proteas in some discomfort, losing two for none to be 113 for three after India posted 334 batting first.
Typically he stole the initiative away in grinding style and after the Proteas were eventually bowled out for 500, India finished the day on 68 for two.
"In the situation that we were in it was important to consolidate a bit and make sure we got back on track after losing a few wickets," Kallis said.
"We basically tried to pace the innings and to keep the scoreboard ticking. It was quite difficult to score because the wicket is quite slow, they put up defensive fields and bowled quite defensively.
"As we got closer to their total we could afford to be more positive. I thought the guys really paced the innings well."
With the tourists still facing a deficit of 98 runs to overcome on the final day, South Africa are favourites to send Kallis out in style.
"We have lost a lot of time in the game but I think there is a result beckoning for us," spinner Robin Peterson said.
"The stats show that on day five at Kingsmead 10 wickets normally fall on the day so hopefully we are on the right side of the result.
"Tomorrow morning's session will be crucial to see if we can push for the win. Luckily we have two wickets already and hopefully the bowlers will come out firing after a good rest."
Speaking of Kallis, he added: "It looks like he is enjoying himself in his last game.
"He richly deserves to do that, all the guys just want him to enjoy his last moments."