Arsenal midfielder Alex Oxlade-Chamberlain joined Liverpool in a deal worth £40m, having spent six years in north London.
The 24-year-old English international refused to sign a lucrative new contract and the club were forced to make him available because of his soon-to-expire contract.
Chelsea and Liverpool fought over Oxlade-Chamberlain, with the former Southampton academy youngster choosing Jurgen Klopp's Liverpool.
He had faced the Reds as a Gooner in a 4-0 drubbing just days before sealing the move.
Alexis Sanchez was close to following his former teammate out of the Emirates exit door but Manchester City failed to get the deal through.
The 28-year-old Chilean forward - who has less than 12 months remaining on his current deal - had publicly spoken of his desire to play Champions League football.
If not sold in January, Sanchez may well leave as a free agent next summer.
The transfer window shut late on Thursday night and we've taken a look at how seven other former Arsenal stars did after they forced a move to progress their career.
Ashley Cole (Chelsea)
Part of the famous 03/04 Invincibles team, the exceptional full-back earned legend status at Chelsea after burning bridges with everyone at Arsenal.
Dubbed 'Cashley' by the Arsenal supporters, Cole went on to win one more Premier League title, four FA Cups, one League Cup, one Champions League and one Europa League title.
Now 36, he is winding down his career at LA Galaxy following a surprisingly unsuccessful stint at AS Roma.
Thierry Henry (Barcelona)
Henry joined Barcelona for only £21m in 2007 and went on to win two La Liga titles, a Copa del Rey, a FIFA Club World Cup and a Champions League in three years at the club.
As he was at Arsenal, Henry was magnificent for the Catalan giants and formed an incredible attacking trio alongside Leo Messi and Samuel Eto'o.
He spent his last four years as a player as the star man of the MLS, briefly returning to north London in 2012 for a fairytale loan spell.
Aleksandr Hleb (Barcelona)
The Belarusian winger also secured his dream move to the Camp Nou but things turned sour very quickly for Hleb.
He made only eight La Liga starts for Barcelona before being shipped out on loan to Stuttgart, Birmingham City and Wolfsburg.
Since leaving Arsenal in 2008, the unattached 36-year-old midfielder has played for 11 clubs.
Emmanuel Adebayor (Manchester City)
Who can forget his famous celebration against Arsenal when scoring for his new club, running the length of the pitch to knee-slide in front of the away supporters?
He underwhelmed since his acrimonious departure from Arsenal, making just 34 Premier League starts at Manchester City before being sent out on loan to Real Madrid and Spurs.
Adebayor has only ever won one Copa del Rey and, at age 33, is now plying his trade for Turkish club İstanbul Başakşehir.
Cesc Fabregas (Barcelona)
Named club captain at 21, Fabregas was loved by Gooners after joining the club from Barcelona as a youngster.
However, his excellent performances piqued Barca's interest and the Spanish midfielder couldn't say no when his boyhood club came calling.
It never went quit to plan for Fabregas in Barcelona but he did win a La Liga title and a Copa del Rey during his time there.
He controversially returned to the Premier League with Chelsea and has since won two Premier League titles at Arsenal's old foes.
Samir Nasri (Manchester City)
He became a very unpopular man at the Emirates when he secured a controversial move to rivals Manchester City.
Nasri failed to win silverware during his hugely impressive three year stay at Arsenal but became a two time Premier League winner in Manchester.
He never really hit the heights many hoped he would and was sold to Turkish club Antalyaspor for next to nothing this summer.
Robin van Persie (Manchester United)
Fans were bemused when Wenger allowed his star striker to join Manchester United in a £24m deal - and rightly so.
Seven successive trophyless seasons at Arsenal were quickly forgotten by the Dutchman when he fired the Red Devils to the title in Sir Alex Ferguson's final season in charge.
At Fenerbahce since 2015, 34-year-old van Persie recently earned a recall to the Dutch national team.