Manchester City confirmed the signing of France midfielder Samir Nasri from Arsenal on a four-year contract on Wednesday in a deal understood to be worth £24 million.
Nasri's long-awaited move to Eastlands was finally completed after the 24-year-old passed a medical and he is likely to go straight into Roberto Mancini's squad for Sunday's Premier League match against Tottenham at White Hart Lane.
"Manchester City FC is delighted to announce the signing of Samir Nasri, who has become Roberto Mancini's fourth signing of the summer," a statement on the club's website confirmed.
"The French international joins the club from Arsenal on a four-year deal and will meet his new team-mates on Thursday. He will wear the number 19 shirt."
City had been chasing Nasri for several months but the transfer looked as though it might stall over the weekend after reports that the former Marseille player's agents were haggling over their cut of the transfer fee.
Mancini added to the confusion by warning Arsenal manager Arsene Wenger that he might pull out of the deal if Nasri played in Wednesday's Champions League tie against Udinese as that would stop him playing for City in the competition.
However, Wenger had already reluctantly accepted that he had to sell an unsettled player with only one year left on his contract.
Nasri, who scored 15 goals and earned a nomination for PFA Player of the Year last season, trained with the Gunners for the final time on Tuesday before being omitted from their squad for the Udinese clash.
He is expected to double his wages as City's Abu Dhabi-based owners take their spending since the end of last season to over £70 million.
"He's a fantastic player because he has technique, he has mentality," Mancini said.
"I knew him when he played for Marseille. I followed him when I was at Inter and we wanted to take him five years ago.
"But I think in the last few years in the Premier League he's improved a lot. Now I think he's a top player."
Mancini splashed out £38 million on club record signing Sergio Aguero, while he had already raided Arsenal to sign French left-back Gael Clichy for £7 million and also bought Montenegro defender Stefan Savic for £6 million.
Nasri's departure is another massive blow for Wenger, who was forced to sell captain Cesc Fabregas to Barcelona last week after accepting defeat in his battle to persuade the Spaniard to ignore the overtures from his home-town club.
While big-spending City have had no problems attracting star signings, Wenger has found it far harder to bring in top talent.
Wenger desperately needs new recruits to improve several weak spots in his squad and moves for Bolton defender Gary Cahill and Rennes midfielder Yann M'Vila said to be high on his agenda, but he has just seven days until the transfer window shuts.