Coach Gregg Clark rested captain Austin Smith and Jonty Robinson enabling them to recover from flu, which has kept them out of the last three Tests.
The South Africans built from the back and have their defensive unit to thank for keeping South Africa ahead, in their first match against Olympic opposition on their European tour so far.
Belgium drew first blood when they were awarded a penalty stroke five minutes into the game with Jerome Dekeyser putting the ball past goalkeeper Rassie Pieterse.
The Belgians' celebrations were cut short by South Africa, a solid build-up from deep in the South African half resulted in Thornton McDade slotting a goal past the Belgian keeper, taking a deflection off a Belgian defender on the way.
South Africa seemed to be spurred on by the equaliser and four minutes later, the visitors' attack were again called into action, with Lloyd Norris-Jones deflecting an excellent Tim Drummond pass into the Belgium area, leaving the keeper stranded.
Belgium responded with a period of sustained pressure, which South Africa dealt with expertly, defenders Andrew Cronje, Lloyd Madsen and Justin Reid-Ross particularly impressive in releasing the pressure and clearing any Belgian attempts at goal.
An extraordinary effort from Pieterse in the middle of the half saw him save three penalty corners in as many minutes as South Africa were forced to weather the Belgian storm.
Five minutes from the interval South Africa turned up the pressure and Lloyd Norris-Jones narrowly missed an effort in finding Ian Haley.
South Africa regrouped, and attacked with determination as they went searching for a third.
The South Africans came out into the second half and picked up where they left off at the end of the first, building their forward movement on solid defensive work.
The opening exchanges of the second stanza belonged to the tourists, making sure the Belgians too had a turn to soak up the pressure as South Africa stuck to their structures and kept Belgium firmly in their own half.
Julian Hykes provided the first real action of the second half when he unleashed a pinpoint shot at goal, beating the Belgium goalkeeper and allowing South Africa some breathing space at 3-1.
But as with the first half, the goal was followed up from the restart with a goal for Belgium, which once again kept the margin to a single goal with a nervy final quarter of the match still to play.
In a match that lived up to its exciting build-up, the last few minutes were relentless in end-to-end action with the South African defence putting in a fantastic effort, thanks to largely to Pieterse who made several goal-saving stops as Belgium came close, but not close enough. – Sapa