Three seasons on, Nasri has very much lived up to expectations and has justified his price tag.
Although he struggled a bit to find consistency in his first two seasons at the new club, the former Marseille playmaker registered a breakthrough 2010-11 season which saw him get a nomination for the PFA Player of the Year and PFA Young Player of the Year awards, which Gareth Bale and Jack Wilshere won respectively.
Though snubbed in the final round for both the awards, Nasri did get the recognition that he deserved with a place in the PFA Team of the Year.
While Nasri has achieved so much at a young age of 23, it mustn't be forgotten that his best years are ahead of him. He's only going to get better.
While that's sure, what's not so sure is where he would play his best years, or at least a part of it.
Nasri has just one year left on his current contract, and speculation is rife that he may leave for greener pastures in search of silverware, having seen Arsenal fail to win a trophy for the sixth season in a row.
Having established himself as one of the best midfielders in the Premier League, it's only normal for a player of the calibre of Nasri to have the desire to fill his trophy cabinet.
If he feels he can't fulfill his ambitions at the current club, he may well decide to move on to a club that's more ambitious in his eyes.
It's important for Arsenal to keep hold of the player and not the other way around. Nasri has had an exceptional season, and what that means is the ball is in his court. He can dictate terms while negotiating a new contract.
He can also demand reassurances from the manager over the new additions to the squad. With clubs like Barcelona and Inter Milan waiting in the wings to pounce, Nasri can afford to play the game in his own way.
Arsenal, on the other hand, simply can't afford to lose one of their best players at a time when they're under immense pressure to put an end to the trophy drought.
It must be questioned how and why Arsenal have allowed Nasri's contract to run down to the extent that negotiation becomes extremely tricky.
It's already feared that Cesc Fabregas might leave his adopted home for his boyhood club this summer. Whether Barcelona could afford him is another matter altogether. If that were to happen, Nasri staying at Arsenal would be that much more crucial to Arsenal's hopes and ambitions for next season.
One stumbling block to Nasri's contract extension could be his desire to play centrally, which wouldn't be possible if the Spanish midfielder stays put.
It's as clear as day that Nasri prefers the attacking midfield slot, a position that he made his own during his successful stint at Marseille.
There isn't any reason why he can't play that role at Arsenal. Arsene Wenger usually mandates that his players adapt to different positions so as to make them better all-round players capable of playing in multiple positions.
The ideology stems from his vision of playing total football, but this sometimes means players remain unhappy despite getting regular playing time under their belts.
The perfect example is Nicklas Bendtner's situation at the club, where he's happy to play week in and week out, but not on the wings. Even a regular place in the starting 11 might not be enough to placate him if it happened to be on the wings.
The situation is somewhat similar with Nasri. A player well suited for the advanced central midfield position might not prefer a role on the flanks forever.
Nasri's outstanding vision, pace, pinpoint passing, fantastic ball control, mesmerising dribbling skills, ability to unleash venomous shots with both feet, tactical awareness and good crossing ability make him a real asset to have in any side.
Now that Arsenal have him already, it's very important for Wenger to secure his long-term future to stave off interest from top European clubs, who would readily welcome the French Footballer of the Year 2010 to their arsenal.
Wenger is under pressure to bring in proven players this summer.
It's essential for Wenger to dig deep into his pocket for pulling the curtains down on the infamous streak of trophy-less seasons, but before that, it's even more important that he successfully persuades the talented, petite French midfielder to extend his contract.