DURBAN (AFP) - Phil Hughes played a thrilling innings as he and fellow opener Simon Katich hit centuries for Australia on the first day of the second Test against South Africa at Kingsmead here Friday. Australia were in a strong position at 303 for four at the close although South Africa fought back after a pummeling during the first three hours of play. Hughes (115) and Katich (108) put on 184 for the first wicket, scoring at better than four runs an over, in a partnership dominated by Hughes, who thrashed 19 fours and two sixes in a 151-ball innings. Fellow left-hander Katich was more sedate in making his runs off 190 deliveries with 16 fours Hughes, 20, reached his century with two successive sixes off left-arm spinner Paul Harris to become Australia's youngest Test century maker since Doug Walters, who was eight days short of his 20th birthday when he made 155 against England in Brisbane in 1965/66. South Africa claimed to have made plans to counter Hughes after his second innings 75 in the first Test last weekend - he made a duck in the first innings - but the little left-hander unleashed a dazzling array of strokes against some wayward bowling. South Africa, seeking to draw level in the three-match series, started the match badly. They bowled poorly on a good batting pitch, dropped two catches and used up both their referrals to the television umpire. The hosts made a comeback later in the day before Mike Hussey, who successfully challenged a leg before wicket decision against him, and Marcus North put on an unbeaten 37 before the close, surviving the second new ball late in the day. Katich was dropped on 55 by Hashim Amla at midwicket off Dale Steyn, while Hughes was put down by a diving Jacques Kallis at slip off Morne Morkel when he had 114. He added only one more before slashing Kallis to gully where Neil McKenzie held a sharp chance. South Africa wasted their first referral when Harris appealed for leg before wicket against Hughes when the batsman was on 81. Not only did television umpire Steve Bucknor uphold Asad Rauf's decision but he awarded Hughes a run because the ball had gone off a bottom edge. Rauf had signaled a leg bye. The South Africans seemed convinced Katich had been caught behind off an inside edge off Morkel when he had 63. It was the first use of 'hot spot' technology, designed to show where a ball made contact, but the picture was inconclusive and Bucknor upheld Billy Bowden's not out decision. Ironically the 'snickometer', which cannot be used in making decisions, later showed Katich had edged the ball. To add insult to South Africa's unsuccessful use of referrals, Hussey referred a decision by Rauf to give him out lbw to Morkel when he was on four. Replays showed the ball had pitched outside the leg stump and Hussey won a reprieve. SCOREBOARD AUSTRALIA, first innings P. Hughes c McKenzie b Kallis 115 S. Katich c Smith b Steyn 108 R. Ponting c McKenzie b Harris 9 M. Hussey not out 37 M. Clarke b Harris 3 M. North not out 17 EXTRAS (b4, lb1, nb8, w1) 14 TOTAL (4 wkts, 89 overs) 303 Falls: 1-184 (Hughes), 2-208 (Ponting), 3-269 (Katich), 4-266 (Clarke) BOWLING: Steyn 18-1-63-1 (1w) Ntini 17-3-55-0 Morkel 17-2-68-0 (6nb) Kallis 13-4-41-1 (1nb) Harris 21-5-66-2 (1nb) Duminy 3-1-5-0. To bat: B. Haddin, A. McDonald, M. Johnson, P. Siddle, B. Hilfenhaus. South Africa: G. Smith, N. McKenzie, H. Amla, J. Kallis, A. de Villiers, J. Duminy, M. Boucher, M. Morkel, P. Harris, D. Steyn, M. Ntini. Umpires: Asad Rauf (PAK), B. Bowden (NZL). TV umpire: S. Bucknor (WIS). Match referee: J. Crowe (NZL).