Arsene Wenger's Arsenal were in decline and lacked balance between defence and attack, according to new head coach Unai Emery.
Arsenal finished sixth last season with 63 points, their lowest Premier League tally of Wenger's reign, before Emery's appointment last summer.
Speaking candidly about the Arsenal squad he inherited, Emery has revealed that defensive structure and making the club more competitive against rivals were the key priorities in his new job.
"With time, only technical quality and offensive freedom were taken care of while losing defensive structure," Emery told Spanish newspaper Marca.
"What I want is to combine both and become more competitive. Arsenal was in a decline. We had to stop this, and begin climbing."
Emery referenced Arsenal's 2003-4 'Invincibles' as the 'perfect combination', but the Spaniard's target in his first season at the Emirates is Champions League qualification.
Arsenal are currently on a 16-game unbeaten run in all competitions and three points off the Champions League places, but have drawn their last three league matches.
Their performance in a 1-1 draw with title-challenging Liverpool was a sign of progress, with several Arsenal players crediting Emery's famed attention to detail for their competitiveness against high-calibre opposition.
Emery said: "We started with an Arsenal that barely won against the top six, even though this year we haven’t done so yet either, but while also having serious difficulty winning away from home, something we have already improved upon."
December could be a defining month for Arsenal, who travel to Bournemouth on Sunday a day after rivals Chelsea and Tottenham play each other at Wembley.
Emery's team then face a long-haul Europa League trip to Ukraine to face FC Vorskla Poltava, before a home north London Derby and Manchester United away in the space of four days.
Emery said: "We’ve had four draws in our last five games and we need to give the team a push now. I’ve spoken with my team during the international break. Our goal is finish in the top four but it’s not easy."
Arsenal's new executive of Raul Sanllehi and Vinai Venkatesham assured fans that there would still be funds to invest without Champions League football, but admitted that a place in Europe's elite competition was an important part of their self-sustaining business model.