In a two-and-a-half hour orgy of pop theatre at London’s O2 Arena on Monday night – the first of four dates at the venue, with two more to follow at Manchester’s Co-op Live – she proved herself to be the original and the best at this game of immersive, spellbinding live performances. “Death or love tonight?” she sings in recent Europop hit “Abracadabra” – a true operatic sentiment if ever there was one. She was visibly emotional addressing the crowd – “Can you feel the love all around you?” she asked – and performed a wildcard track, “Speechless”, a ballad inspired, she said, by British songwriting. She closed out the night with a showstopping “Bad Romance”, flames erupting at the back of the stage: it’s impossible at moments like these to forget that Lady Gaga is one of the greats, a pop revolutionary. The Mayhem Ball is utterly magnificent.