Four years have passed since Lionel Messi last reached a Champions League semi-final and his drought has become a source of unease for Barcelona ahead of their latest attempt tonight.

Manchester United are the ones looking to emulate Atletico Madrid, Juventus and Roma by sending Barca out in the quarters for a fourth year running but for the Catalans, another failure would be unforgivable, not least because of the implications for their captain. "Last season we did the double but we all felt bad about how it went in the Champions League," Messi said in August. "We promise this season we will do all we can to bring that beautiful cup back to Camp Nou."