On 3 October 2007, during Milan's Champions League group stage match against Celtic in Glasgow, Celtic striker Scott McDonald scored the match-winner in the 90th minute to seal a 2–1 victory. As the Celtic players celebrated, 27-year-old Celtic fan Robert McHendry entered the pitch and tapped Dida on the shoulder while running through Milan's penalty area. Dida initially gave chase but after a few steps collapsed to the ground while holding the side of his face, and he was stretchered off and substituted. McHendry later turned himself in to police and was given a lifetime ban from Celtic Park, but UEFA charged Dida with breaching rules upholding "loyalty, integrity and sportsmanship", as it was deemed that he had feigned injury. He was punished with a two-match suspension, while Celtic were fined £25,000 for the pitch invasion. Milan appealed the ruling, feeling the sentence "turn Dida into the protagonist of the incident". Dida never spoke publicly about the incident, but in Milan's first home game following the Celtic match — a 1–0 loss to Empoli on 21 October — he offered a gesture of apology to the fans in attendance by pausing during warmups to bow to each section of the crowd, receiving a round of applause in response. His ban was reduced to one match, causing him to miss Milan's 4–1 first-leg victory over Shakhtar Donetsk on 24 October, but he returned for the 3–0 second leg victory on 6 November. The death knell of Dida's campaign came in Milan's 2–1 derby loss to Inter on 23 December, when he inexplicably dived in the opposite direction of Esteban Cambiasso's game-winning goal, for which he was lambasted by fans and the press. He started Milan's 5–2 win over Napoli on 13 January 2008, but a knee injury the following week saw him replaced by backup Zeljko Kalac, whose own strong form kept him first choice for the remainder of the season, including the Champions League until Milan were eliminated in the knockout round by Arsenal.