Marvan Atapattu and Kumar Sangakkara scored half centuries in the second innings as Sri Lanka piled up a huge 492-run lead over South Africa at the end of the third day in the second Test on Friday.
Sri Lanka, who had earlier bowled out South Africa for 189 as part-time spinner Sanath Jayasuriya took the second five-wicket haul of his career, closed on 211 for four.
Thilan Samaraweera was on 21 not out while Tillakaratne Dilshan was on 23.
The hosts opted to bat again rather than enforce the follow-on to give their bowlers time to recover after two sessions in intense heat and sapping humidity.
Atapattu, who added 46 with Jayasuriya and 96 with Sangakkara as Sri Lanka made a brisk start to their innings, scored 72 while Sangakkara followed his first innings 232 with an aggressive 64 to finish with the second highest match aggregate ever by a Sri Lankan.
Sri Lanka had looked set for a declaration late on Friday as they cantered along at five runs per over before tea, but the loss of Sangakkara and then Mahela Jayawardene (three) after the break slowed their progress.
South Africa, who started the day on 116 for three, lost three wickets in the morning and then collapsed spectacularly after lunch with their last four wickets falling in 19 balls.
Jayasuriya had triggered South Africa's slide late on Thursday by taking two wickets in his first over.
He followed with the crucial scalps of captain Graeme Smith (65) and Jacques Kallis (13) on Friday, as Smith chipped back a return catch and Kallis jammed down late on a skidding delivery and played on.
The 35-year-old then wrapped up the innings by bowling Nantie Hayward to finish with career-best figures of five for 34 from 14.1 overs.
Left-arm spinner Rangana Herath, replacing Muttiah Muralitharan who has flown to Australia for shoulder surgery, also contributed with three quick wickets after lunch to finish with three for 60.
Herath had Boeta Dippenaar (25), the last specialist batsman, caught at silly point off the first ball after lunch before trapping Shaun Pollock (one) and bowling Makhaya Ntini for a duck with an arm ball.
Scoreboard
Sri Lanka (1st innings): (overnight 303-3)
M.Atapattu c Boucher b Pollock 4
S.Jayasuriya lbw Boje 43
K.Sangakkara c Kallis b Pollock 232
M.Jayawardene b Ntini 82
C.Vaas c van Jaarsveld b Pollock 10
T.Samaraweera c Ntini b Kallis 21
T.Dilshan c Kallis b Pollock 3
R.Kaluwitharana c Boucher b Hayward 7
U.Chandana st Boucher c Boje 40
R.Herath b Ntini 7
L.Malinga not out 6.
Extras: (lb-6, nb-8, w-1) 15
Total: (all out, 142.3 overs) 470
Fall of wickets: 1-4, 2-99, 3-291, 4-316, 5-392, 6-399, 7-416, 8-418, 9-437
Bowling: Pollock 30-8-81-4 (5nb), Ntini 33-6-108-2 (2nb), Hayward 17-4-75-1 (1nb), Kallis 17-6-54-1, Boje 34.3-5-102-2, Rudolph 4-0-16-0, Van Jaarsveld 7-0-28-0.
South Africa (1st innings):
G.Smith c & b Jayasuriya 65
H.Gibbs lbw Vaas 0
M.van Jaarsveld c Sangakkara b Jayasuriya 51
N.Boje b Jayasuriya 0
J.Kallis b Jayasuriya 13
J.Rudolph c Kaluwitharana b Malinga 6
B.Dippenaar c Dilshan b Rangana 25
M.Boucher not out 10
S.Pollock lbw Herath 1
M.Ntini b Herath 0
N.Hayward b Jayasuriya 1.
Extras: (b-1, lb-8, nb-8) 17.
Total: (all out, 69.1 overs) 189
Fall of wickets: 1-1, 2-109, 3-109, 4-140, 5-141, 6-166, 7-186, 8-188, 9-188.
Bowling: Vaas 7-3-10-1, Malinga 13-1-51-1 (8nb), Herath 25-6-60-3, Chandana 6-0-21-0, Dilshan 4-1-4-0, Jayasuriya 14.1-4-34-5.
Sri Lanka (2nd innings):
M.Atapattu b Ruldolph 72
S.Jayasuriya st Boucher b Boje 19
K.Sangakkara c Ntini b Kallis 64
M.Jayawardene c Boucher b Kallis 3
T.Samaraweera not out 21
T.Dilshan not out 23.
Extras: (b-6, lb-1, w-2) 9.
Total: (four wickets, 55 overs) 211
Fall of wickets: 1-46, 2-142, 3-149, 4-179
Bowling: Pollock 8-0-46-0, Ntini 4-0-19-0 (1w), Boje 23-6-81-1, Hayward 3-1-15-0, Smith 4-0-15-0 (1w), Kallis 6-2-6-2, Rudolph 7-2-22-1.
