sentences:  United opened their 2006–07 UEFA Champions League campaign with an entertaining 3–2 victory over Celtic on 13 September.Jan Vennegoor of Hesselink gave Celtic the lead with a low shot after 21 minutes.However, United equalised with a Louis Saha penalty, awarded when Celtic keeper Artur Boruc fouled Ryan Giggs, and United took the lead when Saha swept home both his and United's second goal.