ROSEAU (Dominica) (AFP) Hashim Amla continued in his rich vein of form, and struck his third One-day International hundred to help South Africa shake off 'dead-rubber syndrome, and win the fourth ODI against West Indies by seven wickets on Sunday. Amla collected nine fours and two sixes in another sublime innings of 129 from 115 balls, as the South Africans, chasing 304 for victory from their allocation of 50 overs, reached their target from the very last ball in a thrilling finish at Windsor Park. Amla reached his second hundred from 94 balls, when he guided a delivery from West Indies captain Chris Gayle, bowling his uncomplicated off-spin, to third man for three in the 30th over. He shared 59 for the first wicket with the Proteas captain Graeme Smith, 178 for the second wicket with Jacques Kallis, and 46 for the third wicket with A.B. deVilliers that anchored the visitors to victory. It was a great effort from us to chase over 300 runs, and we have to look at the positives from this performance, said Smith. Hashims knock was an incredible innings, and the rest of the guys batted around him very, very well. But I think he must take the credit for a great run chase. We would have loved to have finished the game more comfortably in the last over, and maybe we got a bit conservative there in the end. But we successfully chased over 300 on a second game pitch, and we are happy. When Amla was dismissed, South Africa needed 80 from 76 balls, and J.P. Duminy joined deVilliers to carry them the rest of the way in an unbroken stand of 80 for the fourth wicket. In a dramatic finish however, the South Africans needed one run from the last delivery, following a sensational final over from Dwayne Bravo in which he conceded a single to deVilliers off the first ball, a leg bye to Duminy from the next, and then bowled three dot-balls. DeVilliers however, formalised the result, when he swung the final delivery through mid-wicket, where Darren Sammy fumbled it, and then missed a throw at the bowlers end, as the batsman scrambled to make his ground. The victory handed the Proteas a 4-0 lead in the five-match series, after they won the rain-marred opening match by 66 runs, under the Duckworth-Lewis Method, two Saturdays ago at the Vivian Richards Cricket Ground in Antigua, where they also won the second ODI by 17 runs last Monday, and the third ODI by 67 runs last Friday at this venue. The series concludes this coming Thursday at the Queens Park Oval in Trinidad & Tobago, where the visitors will be chasing a second successive ODI series sweep in the Caribbean. Gayle was obviously, very disappointed by the result, although it came down to the very last ball of the match. Credit must go to Bravo for the way he bowled the final over, he said. But to get 300 runs, and lose was not good. We should have scored at least 30 or 40 more runs based on the start that Dale [Richards] and I gave the team, but we were very disappointing in the middle overs again, too many dot balls. He added: But South Africa are in good batting form right now, and they took the game away from us. We also missed a few catches, and this is the inconsistency. At times, we do well with the bat, and then turn up and do something completely different with the ball. I am very disappointed, and feel heartbroken for our fans, who turned up in their numbers for this match.