Smith hammered 162 not out as he steered South Africa, 1-0 down in the four-match series, to 312 for two in their second innings, batting with impressive power as he struck 22 fours.
Hashim Amla added a ground record 230 for the second wicket with Smith, but could not manage to score a century himself, being caught bat/pad at short-leg for 95 off Graeme Swann to give England their only wicket of the afternoon.
Paceman Morne Morkel claimed two wickets in the opening over of the day after England, replying to South Africa's 291, resumed on 241 for seven.
SCOREBOARD
SOUTH AFRICA (I Innings): 291
ENGLAND (I Innings, O/n: 241/7):
Prior b Steyn 76
Swann c Smith b Morkel 5
Anderson c Smith b Morkel 0
Onions (not out) 4
Extras (LB-6, W-2, NB-1) 9
Total (all out, 88 overs) 273
Fall of wickets: 8-241, 9-241.
Bowling: Morkel 22-4-75-5, De Wet 16-3-36-0, Steyn 22-5-74-4, Kallis 14-2-27-1, Harris 9-0-39-0, Duminy 5-0-16-0.
South Africa (II Innings)
Prince lbw Swann 15
Smith (batting) 162
Amla c Cook b Swann 95
Kallis (batting) 20
Extras (B-8, lb-6, nb-1, pen-5) 20
Total (for 2 wkts; 80 overs) 312
Fall of wickets: 1-31, 2-261.
Bowling: Anderson 11-0-50-0, Onions 13-3-51-0, Swann 33-5-104-2, Broad 15-3-52-0, Pietersen 3-0-6-0, Trott 5-0-30-0.
