Cape Town - Proteas fielding coach CWC Proteas: Will their fielding cut it?
The Proteas play their first warm-up game against Sri Lanka on Friday (11:30) at Sohpia Gardens.
Ontong revealed that the Proteas will maintain their high-standard of fielding during this year's 50-over showpiece.
"The fielding element is very important if you look at previous World Cups, there have always been defining moments in games. We know about those big moments," said Ontong on Wednesday in Cardiff.
"The Proteas always work hard as a fielding team and we know the importance of fielding at a World Cup, we're not taking it for granted.
"We know that all of the other teams are very strong in this department. Obviously, our goal is to be the best fielding team going into the World Cup and that is something we always pride ourselves on and something we're working towards," said the former Proteas batsman.
"South Africa has always been up there in the top three teams when it comes to fielding but I think going into this World Cup, all of the teams are on par. It is about taking opportunities when they're presented to you in the field, so that's going to be very important."
The Proteas have reached the semi-finals in four of their seven World Cup campaigns but have yet to reach a final.
Faf du Plessis' men begin their 2019 campaign when they take on hosts and tournament favourites England at The Oval on May 30.
South Africa's 2019 Cricket World Cup squad:
Faf du Plessis (captain), Hashim Amla, Quinton de Kock, JP Duminy, Aiden Markram, David Miller, Lungi Ngidi, Chris Morris, Andile Phehlukwayo, Dwaine Pretorius, Kagiso Rabada, Tabraiz Shamsi, Dale Steyn, Imran Tahir, Rassie van der Dussen