Adelaide: Graeme Smith survived two close calls to post his 26th Test century and guide South Africa's comeback Friday after Morne Morkel's five-wicket haul swiftly stemmed Australia's rampant run flow in the second cricket Test.South Africa reached stumps at 217 for 2 on day two in reply to Australia's first innings of 550, with Smith unbeaten on 111 and Jacques Rudolph on 25. The tourists were in a radically better position than at stumps 24 hours earlier, when Australia had raced to their second-highest first-day score ever of 482 for 5.Morkel triggered Australia's tail-end collapse when he bowled Michael Clarke for 230 and he finished with 5 for 146, his sixth five-wicket haul in Tests. The Australians squandered an opportunity for massive total by adding only 68 in 21 overs â including a 46-run last-wicket stand â before being dismissed just before lunch on day two.Smith batted with purpose and composure, but had some lapses. He had a big reprieve on 46 when he stepped down the pitch and wicketkeeper Matt Wade missed a routine stumping chance off Clarke's part-time spin.And, after Mike Hussey broke the 138-run opening stand with a direct hit from mid-on to run out Alviro Petersen (54) at the non-striker's end, the South Africa captain was given another batting life.Smith was on 78, and total at 146 for 1, when he was adjudged out after a loud and instantaneous appeal for caught behind off James Pattinson but referred the decision to the TV umpire, who couldn't find evidence of a nick.The South Africans were otherwise untroubled by the Australian pacemen on a flat and true second-day pitch and Clarke used eight bowlers, including all of his part-timers, searching for a breakthrough.Occasional legspinner David Warner provided one in his first over, having Hashim Amla (11) stumped by Wade with a ball that dipped and turned after an erratic few previous deliveries.Smith was content_cn to guide the South African innings at a moderate pace compared with Thursday's crash and bash by the Australians, reaching his century from 198 balls. South Africa haven't lost a Test when Smith has scored a century, a good omen for the team which needs to avoid a series loss to retain its No. 1 Test ranking."What happened yesterday for us, this morning we needed to step up otherwise we were staring at 700," Morkel said. "It was a performance we needed to put to bed . This team always finds a way to fight back and I think in a way you can never count us out."The South Africans will resume Saturday 333 runs behind, but Morkel said they're aiming to be within range of Australia's first innings by stumps â and that's achievable considering 767 runs have flowed in the first six sessions."We always know that day three is the moving day and an important day for us as a unit, so coming here tomorrow there's going to be 11 very hungry South Africans taking the field," Morkel said.After an extraordinary opening day â when Clarke, Warner (119) and Hussey (103) dominated, Friday wasn't a good one for the hosts.Australia lost five wickets for 22 runs â including the dismissal of Hussey off the last ball of the first day â slipping to 504 for 9 before James Pattinson (42) and Nathan Lyon's (7 not out) rearguard stand."It does make you sit back and think about how much of a special day it was, yesterday," Hussey said. "They don't come around real often. But having said that, we have had quite a few phenomenal days against South Africa in the past few years."Hussey said the Adelaide Tests generally produced results late on the fifth day, meaning the match was still up for grabs."I thought South Africa applied themselves very well, batted extremely well, and got themselves in a position where they are still definitely well and truly in the test match," he said. "Tomorrow, in the context of the whole Test match, will be a really key day. If we can bowl really well and restrict South Africa, then we're in a great position to push forward and try to win."If they bat throughout the day and get up close or level or even past our score, then I think it's back to being a really even Test match again."Australia's batting slide started with the dismissal of Clarke, who became the first batsman to post four 200-plus Test scores in one calendar year when he reached his double century late on day one. He added only six to his overnight score before he was beaten by Morkel and lost his middle stump. That dismissal ended his stunning start to the series against top-ranked South Africa, scoring 489 runs before losing his wicket â the 31-year-old Clarke scored an unbeaten 259 in the drawn first Test at Brisbane last week.Morkel also removed Matt Wade (6) and Ben Hilfenhaus (0) and Rory Kleinveldt collected his first Test wicket when Peter Siddle (6) edged him to first slip.The bowling figures weren't flattering for any of the South African bowlers apart from Morkel, but legbreak bowler Imran Tahir took particular punishment and returned 0-180 from 23 overs â the ninth worst figures ever in Test cricket. The 33-year-old Tahir's economy rate of 7.82 an over was the fourth worst of all time.That compounded the problems for a bowling attack which is missing allrounder Jacques Kallis, who injured his right hamstring after taking two early wickets on Thursday, and Vernon Philander, who was ruled out of the match with a bad back.