Fernandes admits his first goal could have been Ronaldo's
Fernandes was named as the scorer of Portugal's opening goal in the 54th minute when his cross seemed to sail just past the head of Ronaldo and dropped into the net with Uruguayan goalkeeper Sergio Rochet confused by Ronaldo's leap.
Portugal's captain appeared to be claiming the goal with his celebrations and was then seen laughing when Fernandes was announced as the official scorer on the stadium's loudspeakers.
"The feeling I had was that Cristiano touched the ball. I was passing the ball to him," Fernandes told reporters. "What matters is that we're going through to the next round after playing a very tough opponent."
Portugal have won their opening two games at the World Cup in Qatar, beating Ghana 3-2 last week before Monday's win over Uruguay, the team that knocked them out of the tournament held in Russia in 2018.
Fernandes, who was a teammate of Ronaldo's at Manchester United until last week when the five-times Ballon d'Or winner and the club parted ways acrimoniously, got his second goal in added time. With Ronaldo already substituted, Fernandes took over penalty-taking duties and scored from the spot.
Coach Fernando Santos brushed aside suggestions from the media that, having already ensured qualification for the knockout phase, he might field a weakened Portugal side against South Korea to give key players a rest.
"First place isn't guaranteed," Santos said. "We will go for top spot, and not just because of Brazil."
Brazil are likely to win Group G which would mean they would then play the runners-up in Group H which is currently topped by Portugal.
Santos' men are due to play their third and final group match against South Korea on Friday.
Asked about the severity of an injury to left-back Nuno Mendes, who was substituted early in the first half, Santos said he would wait and see the result of medical tests.
Portugal centre-half Danilo Pereira missed the Uruguay game after breaking three ribs in training and midfielder Otavio, who was an injury concern before Monday's game, was also left out.