Mokoena, who had struggled to find his best form last year after focusing on the Triple Jump discipline, produced a best leap of 8.05m to secure victory.
He was seven centimetres clear of German athlete Julian Howard, who took second place.
The fourth of five legs in the World Indoor Tour series will be held on Torun, Poland on Friday.
“It's a good start for Mokoena. We believe that he can still jump further in order to secure a spot in the IAAF World Championships in London later in the year.
“He knows how difficult it will be to secure a place in Team ASA, but one thing for sure is that he has experience more than many of the athletes who will be competing against him.
“He must use that experience now more than ever before because he still has a place in international competition,” said Aleck Skhosana, the President of Athletics South Africa.
