Juliano Pinto, a 29-year-old with complete paralysis of the lower trunk, performed the symbolic kick-off at the Corinthians Arena in Sao Paulo.
Using his robotic suit, Mr Pinto kicked the official ball a short distance along a mat laid down by the touchline.
But some observers argued the historic event was not given the attention it deserved during the opening ceremony. The identity of the young volunteer was kept a secret until after the event. His robotic exoskeleton was created by a team of more than 150 researchers led by Brazilian neuroscientist Dr Miguel Nicolelis.
Dr Nicolelis tweeted called the event a "great team effort" and afterwards tweeted: "We did it!!!" "It was up to Juliano to wear the exoskeleton, but all of them made that shot. It was a big score by these people and by our science," he commented.
The neuroscientist, who is based at Duke University in the US, is a leading figure in the field of brain-machine interfaces. In breakthrough work published in 2003, he showed that monkeys could control the movement of virtual arms on an avatar using just their brain activity.
The scientists have been working under the banner of a consortium called the Walk Again Project. In a statement, the consortium said the World Cup demonstration would be "just the beginning" of a future "in which people with paralysis may abandon the wheelchair and literally walk again".
But some TV networks didn't capture the event, prompting criticism on Twitter. Some commentators also took aim at ceremony organizers for apparently sidelining the moment in favor of performing acts. "It's the first time an exoskeleton has been controlled by brain activity and offered feedback to the patients," Dr Nicolelis, a neuroscientist at Duke University, told the AFP news agency