With the fastest goal in Olympic history, Neymar led Brazil back to the gold-medal match.
The Barcelona striker scored 15 seconds into the game and converted a penalty kick in second-half injury time Wednesday to lead Brazil over Honduras 6-0 in the semifinals of the men's tournament.
Gabriel Jesus added two goals in the first half at the packed Maracana Stadium and Marquinhos and Luan scored a goal each in the second.
Brazil has never won the Olympic title, and lost in the final at the 2012 London Games.
"We won and we won well, but if in the final we don't play well again, all of this will be for nothing," Brazil midfielder Renato Augusto said. "We don't want to disappoint the fans. They want us to play well and they want us to win the gold."
The host country will play Germany in Saturday's final. The Germans beat Nigeria 2-0 in Sao Paulo.
Brazilian fans had been hoping for a sort of rematch against Germany, whose senior team embarrassed Brazil 7-1 in the semifinals of the World Cup two years ago.
"Hey Germany, just wait, your turn is coming up," the fans chanted at the Maracana.
Only the gold will be enough for a talented Brazilian team playing at home and considered the main title-favorite in a tournament played mostly with under-23 squads and very few stars.
The Olympic gold medal is the only major trophy the five-time World Cup champions haven't won in soccer.
With Neymar thriving, Brazil was in command from the start in front of the more than 70,000 fans at the Maracana.
It didn't take long for the Barcelona player to put the hosts ahead.
Honduras defender Johnny Palacios had the ball under control at the top of the penalty area but gave it away as Neymar closed in quickly, and the striker took advantage to get on the board. His shot was initially blocked by Honduras goalkeeper Luis Lopez but the ball bounced off Neymar's leg and went into the net.
Neymar, one of the biggest stars at the Rio de Janeiro Games, collided with Lopez on the goal and lay on the field grimacing for several moments before trying to stand. Struggling after several steps, he collapsed again and was stretchered off the field and attended to before being able to return.
"Scoring a goal that early was spectacular for us," Brazil coach Rogerio Micale said. "It helped us break the game open and it made everything easier."
Mexico forward Oribe Peralta previously held the record for fastest goal at the Olympics after scoring 29 seconds into the final in London four years ago, when the Mexicans upset Brazil 2-1 to win the gold. Honduras striker Alberth Elis had tied that mark in a game against Portugal in the group stage at the Rio de Janeiro Games. Janine Beckie took only 20 seconds to score for Canada against Australia in the women's tournament in Rio.
After Neymar's early goal, Brazil was in control and Gabriel Jesus, one of Brazil's most promising youngsters, added to Brazil's lead in the 26th after a pass by Luan, hitting the net as the goalkeeper charged from the goal.
Neymar set up Gabriel Jesus' second goal with a perfect through ball behind a defender. The 19-year-old forward entered the area and hit the top of the net for his third goal at the Olympic tournament.
"I'm happy for the goals but the most important thing is that we made it to the final," said Gabriel Jesus, who before the Olympics signed with English club Manchester City. "It was important to win like this, playing well and with a lot of goals."
Defender Marquinhos scored the fourth goal off a corner in the 51st, shooting from close range after the defense failed to clear the cross into the area, and Luan added another in the 79th after a perfect cross by Felipe Anderson.
Honduras made it to the Olympic semifinals for the first time by eliminating two-time champion Argentina in the group stage and South Korea in the quarterfinals, but its inexperienced team never had a chance against Brazil.
"Any scheme will fall apart when you concede a goal with 15 seconds because of your own mistake," Honduras coach Jorge Luis Pinto said.
After the match, some Honduran players were taking photos with Neymar on the field.
Brazil got off to a slow start at the Olympic tournament, being held to scoreless draws against South Africa and Iraq and becoming in danger of another early elimination two years after the humiliating loss to Germany at the World Cup.
But Neymar and the rest of the squad picked up the pace just in time, beating Denmark 4-0 in the final group match and eliminating Colombia 2-0 in the quarterfinals.
One more win will give them the coveted Olympic gold.