When Marcelo Bielsa summoned prodigious Leeds United talent Archie Gray to a notorious 'murderball' session, vindication was emphatic.
Gray had begun training with the first-team squad and remarkably, aged 15, was named on the bench for a Premier League game against Arsenal in December 2021.
Mark Jackson, who nurtured Gray in Leeds' vaunted academy and as his Under-23s manager, watched the midfielder in the gruelling training-ground game which sees the ball continually in play.
'Marcelo's murderball sessions were so intense, but Archie was fearless and had no apprehension whatsoever,' says Jackson.