While Unai Emery has certainly strengthened his squad over the summer, there are still a handful of players that could have bolstered his ranks even further.
Dutch sensation Donyell Malen scored all five goals for PSV Eindhoven as they beat Vitesse 5-0 this weekend.
He was an Arsenal player for over two years before moving to the Eredivisie club in August 2018 for £540,000.
The star was recently on target on his debut for the Netherlands too against Germany, leaving Arsenal fans wondering how the striker slipped through the net.
But Malen isn’t the only young player to thrive having left the Emirates Stadium in recent years.
Serge Gnabry won the Bayern Munich Player of the Year award last season following his move to the club from Hoffenheim.
The German winger left Arsenal in 2016 under Arsene Wenger after being deemed surplus to requirements in north London, he couldn’t even get into the West Bromwich Albion team under Tony Pulis.
Yet since he has gone onto shine at three Bundesliga clubs before establishing himself as a mainstay in Joachim Low’s German national team.
Arsenal had the chance to re-sign two other former players this summer too.
Midfielder Ismael Bennacer joined AC Milan from Empoli for a fee of £14.5m.
He was with the Gunners from 2015 to 2017 and they decided not to take up their option to bring him back to the club after he won the player of the tournament award at the African Cup of Nations.
Former youth star Jeff Reine-Adelaide also clinched a move to Lyon from Angers for an initial fee of £22.8million.
Upon selling the youngster to Angers for £1.4m last summer, Arsenal inserted a sell-on clause in the deal worth 20 per cent.
That saw them bag a fee of £4.5m which is a minor consolation for the small sum they received for him when he ended his stay the club.
Like Bennacer, Emirates chiefs decided against re-signing the star. Emery had the chance to match any offers Angers received for the attacking midfielder.
All four of these former players could have brought something to the Spaniard’s squad for the current campaign, particularly with the constraints of Europa League football and cup competitions.
Similar mistakes must not be repeated moving forward and there is a lesson to be learnt that can be used to help the development of the likes of Reiss Nelson and Joe Willock.
The Arsenal academy has a track record for producing players who are capable of making a mark on the first team, now it is up to Emery to work with the board and Per Mertesacker to ensure these players make the grade at the club.