“I've been working really hard to represent my country and be successful,” said Rossouw.

“It hasn't gone to plan in the last couple of games. Scoring my maiden century was a relief and I'm very happy.”

After making his debut for South Africa against Zimbabwe in August where he made two duck in a row, the left-hander was averaging just 14.5 from 10 ODIs for his country, which included another three ducks.

Rossouw, on Sunday, finished with 128 from 115 balls before losing his wicket on a day where South Africa amassed a mammoth 439 for two, batting first.

The 25-year-old shared the highest opening ODI partnership for South Africa -- 247 runs from 235 balls -- with by Hashim Amla, who made 153 not out.

The Knights batsman said the experience of Amla helped him immensely.

“In the beginning it was a tough period, Hash took most of the strike. I think I only faced about 10 balls in the first six overs.

“Later he just told me to take it ball by ball and not worry if I only made it to a hundred in the 40th over.”

The young Proteas player, however, was overshadowed by the record-breaking exploits of captain AB de Villiers who plundered 149 from 44 balls after notching up the fastest ODI hundred in history.

“He's the best in the world. Credit to him, he's a freak, you can't make a hundred from 31 balls, it's not right,” quipped Rossouw.

Overall, Rossouw was pleased with his progress ahead of the World Cup starting next month in New Zealand and Australia.

“I want confidence from this series, and what I did today has given me that.

“I want to prove I can bat at the highest levels, and if I can bat like I did today, come the World Cup, I'll justify my position in the squad.”

West Indies wicketkeeper Denesh Ramdin, meanwhile, conceded his side never stood a chance even though they managed a respectable 291 for seven in their 50 overs.

“We didn't get the start we wanted, we lost Chris Gayle quite early and kept losing wickets. So with just one or two small partnerships, we got close to 300,” Ramdin said.

“Chasing 15 runs per over coming down the stretch was a little difficult, but we still tried. It was just too many runs.”