Ashley Young was the saviour for Manchester United, as they rescued a 3-3 draw against Basle at Old Trafford on Tuesday.
United seemed to be cruising through two Danny Welbeck goals in the first half but Basle never lay down, and eventually scored three through Fabien Frei and an Alex Frei double.
United's opener came from a well worked move. Phil Jones brought the ball forward, Antonio Valencia took over and picked out the run of Fabio into the box. He delivered a simple ball that Ryan Giggs cushioned into the path of Welbeck, who found the corner.
Just one minute later it was 2-0, Welbeck running on to a sublime Giggs pass before smashing home.
Basle got back into the game when Fabien Frei cracked in a wonderful volley off the crossbar, before he set up namesake Alex to equalise with his head.
United were stunned when Valencia brought down Marco Streller in the box and Alex Frei lashed home the penalty.
It looked like all was lost for United until Nani's cross found Young, and he headed powerfully past Yann Sommer.
"I think we were careless. It's a wake-up call in many ways. A lack of concentration saw us give the game away really...but we rescued it," Ferguson said.
"To concede three goals at home...the defence and midfield have to be better than that in terms of concentration.
"If you lapse, the quality of the Champions League can make you suffer."