The 20-year-old playmaker has been signed on a long-term deal by the European Champions after a deal was concluded with Oscar’s Brazilian club Internacional this afternoon.
Oscar, who underwent a medical at a private hospital in West London last week, was not planning to complete his move until his Olympic commitments were over.
But the deal was rushed forward by Chelsea after a work permit was obtained yesterday for the young man who destroyed Stuart Pearce’s Great Britain team in a pre-Olympic warm-up match last Friday.
Confirmation of Oscar’s arrival at Stamford Bridge takes Chelsea’s summer spending spree to a staggering £76m.
Roberto Di Matteo’s team have already signed £32m Eden Hazard from Lille, £2m for Hazard’s brother Thorgan from Lens and a further £7m for German international Marko Marin from Werder Bremen.
And Chelsea fans will get an early look at their exciting new attacking midfielder when he plays in Brazil’s opening Olympic game against Egypt in Cardiff’s Milennium Stadium tomorrow.
Oscar's name may not be that well known now, but in no time at all the whole world will know who he is
Chelsea have completed the signing of Brazil playmaker Oscar from Internacional.
The deal is another piece of marvellous long-term business done by a manager who until now has shown a particularly short-term outlook.
At the end of last season Roberto Di Matteo shunted aside Andre Vilas-Boas' patient building plans for Chelsea, reinstating an aging duo of Frank Lampard and Didier Drogba to his team in order to gain immediate results and it earned him a Champions League title, but this summer has been all about revitalising that same squad. And Oscar would be a phenomenal addition to it.
Vilas-Boas will look on ruefully at Stamford Bridge goings-on once more but the North London club know that due to their partnership with the Porto Alegre club they have first refusal on the player, so the only possibility is that Spurs have been financially outgunned and have decided to turn their interest elsewhere.
Oscar: Are Internacional about to see the back of him?
In both a footballing and geographical sense, Oscar is very much a product of Sao Paulo.
He was born in Americana, Sao Paulo State, but was spotted by talent scouts at 13 years of age. They took him to the state capital where he signed for the imaginatively-named Sao Paulo FC - Brazil's most successful side in international competitions.
It was there that Oscar started to dazzle as a young player with his playing style compared to Kaka, another famous alumni of the club. By the time Oscar broke through to the first team at the age of 18, he had helped the Morumbi side to become the first team in Brazil to win six national titles.
He would only make eleven appearances for his boyhood club though, as a disagreement over non-payment of wages saw the youngster attempt to walk out on the club as they refused to pay him. The player seemed helpless, a prisoner held behind the steel bars of a contract until in an unprecedented move, Oscar sued them, and the Brazilian FA allowed him to make the move hundreds of miles south to Porto Alegre where he would sign for Internacional.
There then followed long-term wrangling between the two clubs as to who owed what. Thus when Oscar dazzled in the Brasileirao (the national league) of 2011 with 13 goals and ten assists, no foreign club could try to sign him as it wasn't even clear who he belonged to as the legal battle continued.
The moment that will most brought him to the attention of scouts worldwide, though, was his performance in the Under-20 World Cup in 2011. Having a stellar cast around him was no doubt an assistance, but Oscar's hat-trick from midfield in the final against Portugal won his country yet another world title.
Although much of the global attention since then has been on Neymar and Ganso, as they won the Copa Libertadores with Santos, Oscar has continued to grow as an exceptional talent.
While Neymar's talent marks him out as by far the biggest star in Brazilian football - on a marketing level even more so than the obvious sporting one - Ganso has gone the other way. Following his own fall-out with Santos, he is now being painted as Oscar's replacement should a move to London being completed.
The most important thing to note about Oscar is that he isn't a loping playmaker like Ganso, nor is he a speedy winger like Manchester United target Lucas Moura. Rather he is a mix of the two, boasting a more rounded game and a lot of footballing intelligence.
Oscar is such a talented central midfielder that he could certainly play in the same sort of role as Luka Modric does at Tottenham. And although his tackling is not great and he could do with beefing up a little, the same was said about the Croat when he arrived in England.
With his record of scoring goals and his inherent footballing qualities it is only natural to want to see Oscar play high up the pitch and closer to goal, which would put him in the central attacking role of a 4-2-3-1 at Chelsea, shifting Juan Mata out to the left. When he was younger he sometimes played on the right of that three, but it seems unlikely that we would see him there regularly now. He could be a player that moves further and further back during his career, though, as the likes of Modric - who was a 'number 10' at Dinamo Zagreb - and Danny Murphy have done in the Premier League to help their sides keep possession and build from deeper.
That sort of shift should be some way off though. Just as Sir Alex Ferguson killed the dynamism of a young attacker in Anderson, so any manager that tries to shackle the brilliance of Oscar would be making a big error and his goal in the recent Brazil friendly against Argentina last month shows some of his best attributes.
With plenty of attacking options ahead of him, Oscar slows play down and assesses his options before sliding the perfect pass into a forward. It is then that he flies through the gears, from foot on the ball and stationary one second, he is suddenly flying through a gap in the opposition defence the next, driving beyond the attacking line and then finishing with aplomb.
As for those Kaka comparisons, Oscar doesn't have the same explosive acceleration that his fellow Sao Paulo product used to such devastating effect with AC Milan but he is still speedy. Oscar's eye for a pass and drifts into pockets of space off the ball are arguably better than the now unwanted Real Madrid star.
In the same way that Paulinho of Corinthians (closing in on a move to Inter Milan) has been described as a modern midfielder, Oscar's playing style entirely fits the description of a contemporary attacking midfielder. No longer can a player drift around the pitch hopelessly without the ball, they must involve themselves in several phases of play - in Oscar's case this includes chipping in with goals from deep - as well as having the elegance and ability with both feet that is so desirable in the modern game.
Quite simply he is a player that would benefit any top team and at 20 he is a phenomenal talent with untold potential. If a club can purchase him for the sums mentioned then it is brilliant work considering the figures being mentioned for higher-profile but less able players like Lucas Moura.
The fact that Oscar's contract court case between Sao Paulo and Internacional was only settled a month or so ago (Internacional had to pay £5million to buy him outright) means that there has been no long-running speculation with him.
His name may not be that well known now, but in no time at all the whole world will know who Oscar is.
Blues boss Roberto Di Matteo has been after the gifted attacker for weeks and have now finally got their man after Dave Whelan consented to the move
Victor Moses is on his way to Chelsea in a £9million deal after Wigan supremo Dave Whelan finally let him leave at the end of weeks of talks.
The young Nigerian international will sort out personal terms and go through a medical as Whelan takes less than his original demand but accepts the player’s exit.
Moses will leap at the chance of joining the double winners as he goes back to London where he cut his football teeth with Crystal Palace.
Blues boss Roberto Di Matteo has been after the gifted attacker for weeks, as MirrorFootball first revealed on June 18 – but the fee and terms proved a problem as Whelan rejected low offers and held out for more.
Mr Chairman: Wigan Athletic owner Dave Whelan has finally allowed Victor Moses to leave for Chelsea
In the end, Whelan relented because he told Moses he would let him go when the price was acceptable, and now boss Roberto Martinez will get a chunk of the cash to spend.
Moses’ old club Palace are due a slice of the deal – up to a possible £2m.
Chelsea also plan make-or-break talks with Marseille on Monday to try to land Spanish right-back Cesar Azpilicueta.
Not sure what's the point of getting Moses....