Two of the planet's most dangerous strikers couldn't produce a goal between them.
Ronaldo rattled a 30-yard strike off the left post in the 11th minute for Portugal, but Ivory Coast otherwise created the better opportunities.
"It was a tight game, not many occasions to score," Ivory Coast coach Sven-Goran Eriksson said. "I thought if any team was going to win, it was we. We created some more chances than they did. I am very, very happy with the performance. If you think about discipline and organization, I think we were organized for all 90 minutes."
Drogba came on as a 66th-minute substitute for fellow Chelsea striker Salomon Kalou after FIFA cleared him to play with a cast on his right arm, which he broke in a warm-up match against Japan on June 4.
He was ruled eligible only shortly before kickoff at Nelson Mandela Bay Stadium in Port Elizabeth, and his entrance was greeted by huge cheers, vuvuzelas drowning out the drums of Ivorian fans for the first time in the match.
"It probably was the most important goal of my life," Reid said after scoring in second-half injury time to lift New Zealand into a 1-1 draw with Slovakia in Group F in Rustenburg. "I didn't see the ball until late. I knew that if I got it on target and didn't hit it too hard, I could just guide it in."
Which he did before sprinting to the sideline, his shirt removed, as teammates chased him. "I will take it," Reid said of the yellow card. "It was worth it."