Mulder led South Africa to a commanding 369-run second-innings total against Zimbabwe in Bulawayo, as he contributed with a career-best 147 off 206 balls.
Having scored his first ton against Bangladesh last year, the 27-year-old says getting to triple figures in test cricket is always a big achievement, as he emphasised the importance of team victory over the personal milestone.
"I've worked really hard on my batting, I always have, and I've been someone who's batted in the top four or top five most of my career, and in the Test team I've always had to kind of figure things out," said Mulder.
"I think Test cricket is incredible [difficult] and there are no easy runs in Test cricket, so having more than one century for my country is really special, especially in Test cricket.
"I'm going to keep pushing and keep trying to be better, and stay greedy, as Temba [Bavuma] always says to me.
"But I think the important thing is that we're in a good position as a team, so while my individual things are pretty cool, a week from now everyone's going to forget about my 100 and it's about whether South Africa won the Test match, and that's where my head's at.
"Hopefully I can get another 100 soon and make it three in 12 months."
Mulder fell just shy of the 150-run mark as he looked to go big off a short ball on 147, and was caught by Takudzwanashe Kaitano at deep mid-wicket, and admitted to being a bit surprised and disappointed after hitting the ball so well.
"To be honest, I hit that ball really well – I was chuffed with my execution, when I hit it I thought it's in the trees, to be honest, and then it looked like the wind brought it back," he added.
"But I think I did a lot of good work to get there, and for me it's more about the mental processes that I had to consistently do to get into that position, because I don't think the wicket is flat.
"I think we had to play well and respect the good ball all the time, and I'm really happy with how my mental processes went, and to finally get the 100 is pretty special."