Fans and pundits alike are tipping Barcelona star Neymar to be the catalyst for La Selecao in their homeland, but the Blues defender disagrees.
The 22-year-old Neymar is the talisman for his national side, and a lot will rest on the shoulders of the Barca forward, with the whole nation expecting their team to emerge victorious at the World Cup.
However, Ivanovic has backed his teammate Willian to be the star at the South American tournament.
The Daily Mail quotes the Serbian as saying: "Willian is a great player. He has that ability to make the difference all of the time. He refreshed the team when he came on [against Serbia].
"He was pushing it forward, moving it faster but still doing really hard defensively. There's no doubt he can make a big difference.
"Oscar is brilliant as well though, They both give Brazil and Chelsea a lot."
Meanwhile, Brazil boss Luiz Felipe Scolari feels that he has a wealth of talent at his disposal ahead of the tournament.
"It's not just Willian," he said. "I have Bernard and Fernandinho. If I am in trouble I know I can rely on these players for a good performance.
Brazil signed off for their World Cup preparations with a 1-0 win against Serbia on Friday evening. Fred's second-half goal just before the hour-mark was enough, despite them being booed off at half time in Sao Paulo.
The five-time World champions begin their campaign with the opening game of the tournament against Croatia on Thursday, before meeting Mexico and Cameron on June 17 and 23 respectively.