Zimbabwe 30 for 4 (Morkel 3-20) trail South Africa 309 for 9 dec (Markram 125, de Villiers 53, Jarvis 3-57, Mpofu 3-58) by 279 runs
Port Elizabeth: Aiden Markram hit his second century in three Test matches and Morne Morkel produced a devastating spell of new ball bowling as South Africa took command on the first day of a four-day, day-night Test against Zimbabwe at St George's Park on Tuesday.
Markram's innings of 125 was the mainstay of South Africa's 309 for nine declared before Morkel, bowling at high pace under lights in South Africa's first home floodlit Test, took the first three wickets to leave Zimbabwe reeling at 30 for four at the close.
Morkel trapped Hamilton Masakadza leg before wicket with the first ball, dismissed Chamu Chibhabha for six with the help of a blinding catch by Temba Bavuma at fourth slip and had Brendan Taylor caught behind for the second duck of the innings.
Vernon Philander followed up by trapping Craig Ervine leg before for four.
New cap Ryan Burl showed resolve in batting through to the close on 15 not out while Morkel had figures of three for 20.
With South Africa losing five wickets for 58 runs after the dinner break, a total of nine wickets fell for 88 runs in a two-and-a-half hour floodlit session.
Opening batsman Markram, 23, who was caught behind off what proved to be the last ball before dinner, continued a dream start to his Test career.
Although he was run out for 97 in his first Test innings against Bangladesh in September, followed by 15 in the second innings, he made 143 in the first innings of his second Test against the same opponents.
Markram took 104 balls to reach fifty but accelerated to post his century off 175 balls with 13 fours and a six. He added another four and a six before falling to the 204th ball of his innings.
Markram shared stands of 72 with fellow opener Dean Elgar (31), 96 with stand-in captain AB de Villiers (53) and 78 with Temba Bavuma (35 not out).
De Villiers, making a comeback to Test cricket, made an aggressive 53 off 65 balls.
He was the captain in his most recent two Tests, against England in January 2016, but then suffered a long-term elbow injury before deciding to take a break from long-form cricket.
Wicketkeeper Quinton de Kock strained his right hamstring while running between wickets and De Villiers had to take the gloves at the start of the Zimbabwe innings.