Lee Hendrie scored in the third minute to put Aston Villa in front, but it didn’t matter. Arsenal would score and score again, and Arsenal would win. Because Arsenal always won. Sure enough, Robert Pirès equalised from the penalty spot, and after Thierry Henry had given the home side the lead on the stroke of half-time, Pirès swept home his second goal to seal a routine 3-1 victory. “I don’t think they would have panicked at even two goals down,” beaten manager David O’Leary said. “They’ve got such belief.” It was Oct. 16, 2004, and Arsenal had just extended their record-breaking unbeaten run to 49 Premier League games. The defending champions were five points clear at the top of the table, having scored almost twice as many goals as any other team in the division, and with Villa duly dispatched, thoughts quickly turned to a midweek trip to Panathinaikos in the Champions League. With the benefit of 15 years’ hindsight, that mild, overcast October afternoon in north London turns out to have been the last time Arsenal looked unbeatable. Eight days later, their unbeaten run came to an end in a 2-0 defeat at Manchester United — Ruud van Nistelrooy…