As the EU – and the world beyond – continues to grapple with the COVID-19 pandemic, Janis A. Emmanouilidis and Fabian Zuleeg look back at a previous time of intense pressure and discord in the Union, the euro crisis, to glean valuable lessons and traps to avoid.They argue that the EU cannot afford to stall the process of unconditional solidarity any further. The legitimacy of the Union is at stake. The 2010-2015 euro crisis already highlighted the implications of a highly interdependent Union; the importance of acting quickly, forcefully and boldly; and the need to roll out decisive joint action and an effective European strategy.Emmanouilidis and Zuleeg apply these lessons to today’s health crisis to remind European, national and regional leaders that we stand together, and fall together. Unconditional solidarity guided by the principle of enlightened self-interest will be the Union’s answer to the crisis.Secondly, the EU should act early and forcefully if they are to get ahead of the curve. The Union should thus jointly set up and finance a common COVID-19 recovery and growth fund, and then implement a coordinated European ‘exit management strategy’. Rather than concentrating on one particular instrument, the EU institutions should assemble a convincing package deal that is explicitly supported by member states.Finally, all EU leaders must recognise that absolutist positions will undermine the search for an effective European strategy to manage and eventually overcome the COVID-19 crisis. Disunity, fragmentation and distrust will result in failure – not only for the crisis but also for the foundation of the Union itself.