By James Cormack Aston Villa are readying themselves for their first European semi-final in over 20 years when they welcome Olympiacos to Villa Park for the first leg of their Europa Conference League tie on Thursday. Unai Emery has earned a lofty reputation thanks to his work in European competitions and has guided Villa into the last four of the Conference League having previously lifted the Europa League with Sevilla and helping Villarreal into the Champions League semi-finals. The Premier League side were forced to overcome Lille on penalties in the quarter-finals after surrendering a 2-1 …