The skipper slotted home a penalty in each half - one to Alex Remiro's right and one to his left - as United recovered from going a goal down through Mikel Oyarzabal's own spot-kick.
Bruno then sealed victory in the tie by hitting the bottom corner late on, after Alejandro Garnacho had shown awareness and patience to find him clean through on goal.
Our no.8's second treble in a red shirt - his first came against Leeds in August 2021 - took him to 41 combined goals and assists in the Europa League and we've been informed by Opta this is a new competition record, dating back to when the tournament was rebranded in 2009.