sentences:  Benfica took the lead midway through the first half when Nélson drilled in a 25-yard stunner.Nemanja Vidić drew United level with a fine header in stoppage time at the end of the first half, and Ryan Giggs put United ahead with another header, before Louis Saha finished off the scoring from 12 yards.The draw for the first knockout round of the Champions League was made on 15 December 2006 in Nyon, Switzerland.