He reached the landmark with the last ball of the fourth over‚ a delivery from Subashis‚ that he drove through mid-on for four.
Then Elgar set about repairing the damage he caused by running out Markram for 97 on his debut in Potchefstroom in the first Test.
Bangladesh won the toss and‚ perhaps‚ declined to bat first on what appeared to be a sound surface.
It seems the nightmare of their second innings in Potch‚ where they were dismissed for their record low of 90 despite good batting conditions‚ remains alive in their heads.
South Africa won that match by 333 runs‚ but in the winning of it Morne Morkel was ruled out for up to six weeks with a torn side.
Wayne Parnell replaced Morkel in the team for the second Test.
Bangladesh made four changes‚ the most important of them forced — Soumya Sarkar replaced Tamim Iqbal‚ who has a thigh problem.