"A complacent strategy focusing on slow change rather than pressing crises is losing the EU its battle with Russia for influence" in the East, the analysts declare.
The report predicts dire consequences for the six Eastern neighbours of the EU (Belarus, Ukraine, Moldova, Georgia, Azerbaijan and Armenia) and for the Union itself unless the bloc's leaders improve their act.
EU leaders should "stop placing a lazy bet on a strategy of 'enlargement-lite' - ignoring that the six countries are deep in the worst political and economic crisis since their independence," write Popescu and Wilson.
"Without the accession carrot, the countries of the Eastern neighbourhood will not naturally gravitate towards the EU, as Brussels policymakers seem all too often to assume," insist the authors. "It's time for the EU to understand that if they do not help Eastern European states to deal with the crises ravaging the region, Russia will," they claim.
"Distrust and fatigue increasingly cloud the EU's relationship with its Eastern neighbours. With Russia's influence growing, the EU must work to save the region from turning into a quagmire of half-reformed or failing states," they warn.
All the neighbourhood countries (except for Belarus) trade more with the EU than Russia. But "Russia skillfully uses its smaller economic muscle to gain bigger political clout through strategic investments and realist politics," the analysts explain.
Moreover, "whereas Russia provides visa-free access and encourages migration, citizens of Ukraine and Moldova can no longer visit Schengen EU without visas".
Thus, Popescu and Wilson stress that "bureaucratic strategies like the Eastern Partnership urgently need to be complemented by dynamic, country-specific measures, to help the neighbourhood states resist short-term political and economic pressures".
They also recommend EU policymakers to "rekindle [their] appeal to neighbourhood states," and call for liberalisation of the visa regimes and the organisation of a "27+6" foreign ministers meeting.
"Without sacrificing its own interests or principles, the EU must look for ways to work with Russia to make the region more stable," insist the authors.
"If the EU continues to downplay the importance of the region, it can expect to suffer the consequences in the years to come," they conclude.