Cape Town - Jacques Kallis hit a calm, chanceless century to keep South African hopes alive on the first day of the third Test against England at Newlands on Sunday.Kallis made 108 not out as South Africa recovered from 127 for five to reach 279 for six at the close.It was a crucial innings by Kallis for a team under pressure after losing the second Test in Durban by an innings and 98 runs to go 1-0 down in a four-match series.He shared three half-century partnerships as South Africa clawed their way back into contention after a poor start.South Africa slumped to 51 for three before Kallis and AB de Villiers put on 76 for the fourth wicket. But then off-spinner Graeme Swann took two wickets in two balls to plunge them to 127 for five.But wicketkeeper Mark Boucher hit an aggressive 51 and helped Kallis add 89 for the sixth wicket, before Dale Steyn partnered South Africa's senior batsman in an unbeaten seventh wicket stand of 63.It was Kallis' 33rd Test century, his sixth at Newlands and his third in successive Tests against England at the ground.Kallis reached his century shortly before the second new ball was due when he hit a full toss from part-time spinner Kevin Pietersen to the wide mid-off boundary for his 11th boundary. He had faced 173 balls.Rain delayed the start of play by half an hour and Andrew Strauss' decision to bowl first paid an early dividend when James Anderson had Ashwell Prince caught behind for nought off the fourth ball of the match.South Africa could have been two down three balls later when Graeme Smith, on one, edged Graham Onions' first delivery into the midriff of Swann at second slip.But Swann could not hold the chance. Although regular second slip Paul Collingwood was passed fit to play, he was fielding at fine leg to prevent further damage to a dislocated left index finger.Smith and Hashim Amla put on 45 for the second wicket before Amla was leg before wicket to Graham Onions for 14. Smith made 30 before being caught behind off Anderson off the first ball he faced after lunch.A shortened morning had been played under overcast skies but the sun came out after lunch and Kallis and De Villiers batted brightly, adding 76 runs off 126 balls.Swann, man of the match in the first two Tests, ended a 76-run third wicket stand between Kallis and de Villiers when he had the latter smartly caught at short midwicket by Strauss for 36.JP Duminy then suffered his second successive first-ball dismissal when he pushed forward tentatively and edged a catch to wicketkeeper Matt Prior.Boucher was in sparkling form as he made 51 off 87 balls before he was leg before wicket to Broad.With the clouds again sweeping over the ground, Steyn provided surprisingly capable support until bad light stopped play 20 balls after the second new ball was taken.Veteran fast bowler Makhaya Ntini was dropped from the South African team and replaced by Friedel de Wet.