There were few strong offensive opportunities, with only 12 total shots on goal and just three of those on target.
Ronaldo charged up the crowd in the 11th minute with a powerful kick from 25 yards out that had Ivory Coast goalkeeper Boubacar Barry beat but caromed off the post.
Drogba didn't start the game because of a broken arm but came off the bench in the 65th minute to try to give Ivory Coast a lift.
His best chance came in stoppage time when he had control of the ball in front of the left section of the goal and had drawn Portugal goalkeeper Eduardo out. Drogba sent a smart clearing pass to the right but no Ivory Coast teammate was able to reach it in time for a shot.
Brazil grabbed the early Group G lead with its surprisingly close 2-1 win Tuesday over North Korea, which played the world's No. 1 team even for 55 minutes. Still, after the first set of round-robin games, Brazil leads the group with 3 points while Ivory Coast and Portugal each have 1 and North Korea none.
The second round of Group G games has Brazil playing Ivory Coast Sunday and Portugal taking on North Korea Monday.
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