MANCHESTER: The memories of Manchester United's defeat to Celtic are still fresh for Alex Ferguson. As the two sides prepare to meet on Tuesday in the Champions League, the United manager can't help looking back at the 1-0 group stage loss to Celtic in 2006 that followed a 3-2 victory at Old Trafford."Last time we could have scored more goals in the home game but at Celtic Park we forgot the essential issue of putting the ball in the net," Ferguson said. "We played brilliant football but forgot the real reason for going to a game of football is to win it."Adding to Ferguson's irritation was the satisfaction it gave Celtic manager Gordon Strachan, who has a prickly relationship with his former coach. Strachan played for Ferguson at Aberdeen, Scotland and United.Ferguson, a former player with Celtic's fierce Glasgow rival Rangers, eagerly anticipates facing Scottish sides.