Updated at 4:47 a.m. ET: LONDON -- A few miles from London's Olympic Stadium, partying Brazilians gathered Sunday night to watch the closing handover ceremony on giant screens -- and to contemplate the work ahead of them before the 2016 Summer Games in Rio de Janeiro.
Organizers of Rio 2016 have been spreading their buzzwords of "passion" and "embrace" but after a London 2012 Games that has been praised for its smooth delivery and the triumphant sporting achievement of the host nation's athletes, they are already under scrutiny.
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Jacques Rogge, president of the International Olympic Committee, on Sunday urged Brazil to do everything it could to ensure a better performance in four years’ time after the country came 22nd in the medal standings with just three golds.
“You need gold medals, that is so important for the mood of the public and the general atmosphere of the Games," he told a press conference.
"We had to wait a few days for the first bronze, but from then on you couldn’t follow the pace,” he said about the British team’s results. “We’re relying on exactly the same [from] our Brazilian friends.
“If you want a good result in Rio 2016, it’s time to start and kick off as soon as possible,” Rogge added, noting the U.K. had won just one gold medal at Atlanta in 1996.
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As London officially handed the Olympic baton to Rio at the closing ceremony, Brazilians and other revelers gathered at "Casa Brasil" -- a temporary promotional space for Rio 2016 at London's historic Somerset House -- to watch the event on giant screens.
“It’s a time to show your city, show your culture. I hope Rio can have a ceremony like that as well,” said Joao Brasil, 34, a DJ who has lived in London for three years but plans to return to Brazil for the soccer World Cup in 2014 and the 2016 Olympics. He said being in London for 2012 Games had been “amazing.”
"The party is beautiful it is really exciting to be here before being in Brazil, in Rio… It’s really emotional actually.”
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He said British friends had been unimpressed before the start of the Games, but had been swept away in the wave of enthusiasm that hit after they actually started with film director Danny Boyle’s opening ceremony.
While Brazil only earned three gold medals, Brasil said they had only narrowly missed out on a number of others. And even if Brazil did not do well in 2016, he said the people would still be enthusiastic hosts.
“It’s going to be wild,” he said.
He was among a crowd watching the ceremony in the courtyard of the grand 18th-century building, overlooking the River Thames, which was flooded with light in the green, yellow and blue colors of the Brazilian flag.
Brazilian music, including an appearance from Brazilian Beatles tribute band called Sargento Pimenta, added to the carnival atmosphere. When the handover ceremony was complete, flags proclaiming 'Welcome to Rio' were unfurled from the roof of the building and the crowd began to dance wildly and wave Brazilian flags.
'The world is going to embrace Brazil'
Danilo Costa, 28, a lawyer originally from Sao Paolo, now living in London, said he had initially been “skeptical” and “worried” about the Brazilian section of the closing ceremony, but had been won over.
“I’m much more impressed by what they did, than what the British did in Beijing,” he said. “I think that was really good, I’m really impressed.”
”I think the world is going to embrace Brazil… and have lots of fun,” he added.
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Costa said he thought the Games would enable his country to show its true nature to the world.
“We can benefit a lot from this. It looks like our image abroad is a lot worse than the reality,” he said.
Nicole Spinelli, 24, from Sao Paolo, Brazil, who has been studying for a finance degree in London, said she was “very excited” about the Rio Games, providing it was as well organized as those in London.
“If they can keep it organized and things can run properly, we will enjoy the party, otherwise it’s going to be a mess – without any party,” she said.
Read more London 2012 coverage from NBCNews.com
Fellow finance student Rosemary Fernandes, 30, from Santa Katarina, Brazil, said she hoped Rio 2016 would have as good an atmosphere as the London Games, saying “people were cheering all the world,” not just the British athletes.
On Brazil’s sporting performance, she added, “they didn’t do well here so hopefully they will do better in Brazil.”
Earlier in the day, Rio 2016 officials were on hand to explain their Games bid, and to sell Brazilian culture - - including free yellow Olympic T-shirts -- to lines of tourists and curious British Olympic spectators.
“I don’t think there will be any empty seats at Rio,” said Philip Nagenda, who toured Casa Brasil with friends after watching his native Uganda beat Kenya in the men’s marathon final in central London. “I think people are very passionate there and will turn up.”
His friend Ronald Mukasa, also from Uganda, said: “I think Rio will be more colorful, maybe have a bit more character than London – but it will be hard for them to get the transport as good. Everything has been well organized in London.”
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Jim Armitage, from Reading, Berkshire, said: "I think Rio will be spectacular but London has so many historic and symbolic venues, such as the beach volleyball in Horseguards Parade. I know Rio has the Christ statue and Copacabana beach but I think London will be a very hard act to follow."
His wife Sue added: "I hope Rio is able to recreate the great sense of excitement and involvement in the Games, particularly with screen so you can follow all the action. We were at the sailing in Weymouth [on England’s southern coast] and watching Andy Murray win gold at the tennis on the screen and it felt as if we right were at Wimbledon, too.”