Mauricio Pellegrino briefly donned the shirts of both Liverpool and Barcelona during his 16-year playing career - but it's his exploits in management that provide the most recent relevance with his former clubs.
The Argentinian is currently the man in charge at CD Leganes in Spain. Back in September, just a matter of months after taking the job, he guided the La Liga side to a shock 2-1 victory over Barcelona.
Meanwhile, he spent last season in the Premier League at Southampton, facing Jürgen Klopp's Liverpool twice and falling to defeat on both occasions.
So, there's an obvious question that springs to mind prior to the first leg of the Champions League semi-final between the Reds and the Blaugrana: Which opposing frontline kept him up at night the most?