updated 8:50 p.m. ET Oct. 9, 2007

RIO DE JANEIRO, Brazil - Brazil began a five-day preparation period Tuesday ahead of its debut in 2010 World Cup qualifying.

Led by Ronaldinho and Kaka, Brazil will visit Colombia on Sunday and play Ecuador three days later at Maracana stadium in Rio de Janeiro.

The duo arrived at Brazil's training camp outside Rio along with 20 other players summoned by manager Dunga for the first two matches in the South American qualifying tournament.

"The World Cup starts now," Kaka told reporters. "We know it's a big responsibility and we need to get good results early in these initial matches."

Dunga, a former player who replaced Carlos Alberto Parreira following Brazil's quarterfinal elimination at the World Cup in Germany, has revamped the Brazilian squad as it tries to secure a spot at the World Cup in South Africa.

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"All 22 players here are fighting for a spot in the starting lineup," Dunga said. "We still need to make some evaluations before we decide who will play."

Only nine players from Dunga's current list were included in last year's World Cup roster. AC Milan striker Ronaldo and Inter Milan forward Adriano are some of the players left out from Dunga's team.

Dunga will not be able to count on injured Chelsea defender Alex, who was replaced by Werder Bremen's Naldo for the first two matches.

The team underwent a light physical session on Tuesday.

Brazil will play two other qualifying matches later this year against Peru and Uruguay in November.

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