The Internacional striker took his tally to a tournament leading six as he and Romulo ensured victory for Mano Menezes' side and moves it one step away from a maiden gold medal
Mano Menezes' side started slowly but found its stride to put an end to South Korea's 18-game unbeaten run, lining up a place in Sunday's final against Mexico, who overcame Japan 3-1 earlier in the day.
Despite playing 120 minutes in the quarterfinal against Team GB, South Korea began the game far stronger than Brazil creating a number of early chances that served as a wake up call to the tournament favorite.
After a gentle opening 10 minutes, a short South Korean corner led to a neat piece of footwork and backpost cross that saw Kim Hyun-Sung rise to seemingly head into an empty net. Only the presence of Ji Dong-Won and an inadvertent block kept the scores level.
The Sunderland striker was the lead protagonist in the opening stages, creating another chance for Kim as he clipped a diagonal ball to the backpost. His strike partner rose above the 19-year-old goalkeeper Gabriel and forced the ball back across the box for the onrushing Ji but he was denied by clearance more suited to martial arts than football – averting danger and fortunately avoiding conceding a penalty.
Brazil eventually buzzed into life and forced Beom-Young into a series of saves beginning with Damiao's low left-footed drive from the edge of the box that was just diverted to safety.
Seconds later a weak back-pass forced Beom-Young from his goal and into a sliding tackle on Damiao on the edge of the box. Though the block was firm, the rebound fell to Sandro but South Korea were relieved to see his tame first-time chip easily cleared off the line.
Romulo continued to build the pressure further with a precise curling effort that Beom-Young pawed into the path of Damiao, but the 23-year-old's cross-shot found neither the goal or a team-mate.
For all Beom-Young's good work, it was undone on the 38th minute as Mano Menezes' side took the lead through Romulo.
Sandro robbed South Korea of possession on the halfway line and Neymar picked up the loose ball, immediately shifting it inside to Oscar. The new 25 million pound Chelsea signing carried the ball to the edge of the box before sliding a neat pass to the overlapping Romulo who struck his shot low and under the keeper at his near-post.
It was a touch cruel on South Korea, who had been the better side for the first 20 minutes but Brazil struck at a crucial time and took a 1-0 lead into the break.
Hong Myong-Bo's team emerged for the second half displaying the same positive ethos that caused the Selecao problems in the first period and it was extremely unlucky not to be awarded a penalty as Kim Bo-Kyung was tripped by Sandro in the box as he ran to collect a through ball.
But the early rally was quelled by Brazil as Marcelo galloped forward from left-back to link up with Neymar. The much-vaunted striker played a one-two on the edge of the box, before hitting the byline and cutting the ball back for the waiting Damiao who made no mistake from 15 yards, smashing the ball back across goal to double Brazil's lead.
And it took just five more minutes for Damiao to find his second of the game as good work from Neymar and Oscar saw an attempted pass to the Santos striker deflect into his path.
The Internacional forward who has been heavily linked with a move to Tottenham, reacted sharply to toe-poke the ball into Beom-Young's bottom right-hand corner from roughly 12 yards.
Hulk and Alexandre Pato were introduced for the final 15 minutes and Brazil relaxed, switching to the showboating style synonymous with the national team.
But it was Neymar who continued to exude the flamboyant nature that has made him such a watchable figure. His run in the 90th minute down the left flank and into the box included stepovers, a sudden stop and a beautifully flighted cross that was just misread by Oscar, preventing Brazil making it four. And that was how the game stayed.
South Korea will look back at this tournament with pride but ultimately it came across a team, that when in the mood, has too much attacking potency to contain. The final scoreline ensured Brazil maintained its record of netting three goals in every Olympic game and will certainly ensure it retains its tag as favorite to win a maiden gold medal.