Ahead of this week's Rolex Series event, Grace said: "I can't believe it's 12 months already. Time flies.
"It was great. Obviously it's one of those moments in your career you'll never forget, almost a life-changing moment, winning South Africa's biggest event - I would like to say.
"Winning a tournament you grew up watching - and you see some legendary names on the trophy as well - it's great.
"It's great being back. A nice thing about days like today is you go out and relive those moments. You kind of remember where you made those crucial putts and where you made those crucial shots and things like that.
"I'm super excited to be back here obviously. This is a tough week defending. It's never easy, but I've done it before, so hopefully we can do it again.
"The thing about this place is you have to keep it in the fairways. The greens are pretty small, as well.
"So if you can give yourself chances in the fairways getting to the greens, then you're going to do pretty well out here."
Fellow South African Charl Schwartzel, who has 11 European Tour titles to his name, is happy to be back at an event that means a lot to him.
He said: "Obviously as a South African, this tournament is really close to us and it's the first tournament that I came to watch live and watch your heroes play.
"For us, I think it's probably more special, and for the foreigners it's a great tournament.
"Sun City is a great venue. It's always really good to be back here."
China's Haotong Li is hoping to build on last year's final round when he tees it up in South Africa this week.
The in-form 23 year old, who was beaten in a play-off by World Number One Justin Rose at the Turkish Airlines Open last time out, carded a closing 64 12 months ago to finish fourth.
And he will take the positives from that strong finish into this week.
He said: "It was a good finish, so there are a lot of positives to take into this week and hopefully I can have a good week here.
"It has been a very, very good year for me so far. I mean, I just have to stay positive and just need to play my best."