The competition's holders salvaged an away point thanks to a late Ryan Giggs header after Scott McDonald's early opener for the hosts.

"The result does no harm, of course. We didn't lose and the performance in the second half was the most encouraging thing," Ferguson said after the game.

"We deserved to get a point but with minutes to go you think you are going to lose it, that it is not going to be your night.

With one eye on next Saturday's Premiership clash against rivals Arsenal, Ferguson started the Celtic game resting Wayne Rooney, Dimitar Berbatov as well as keeper Edwin Van Der Saar,

"Now we are ready for Saturday's big game against Arsenal," said the 66-year-old.

Courageous Scots

Ferguson also praised the Celtic team as well as their fans for their courageous performance against his team.

"You go to a lot of European games, in Italy for example, and they're not even full. Barcelona and Real Madrid have atmosphere, and Bayern Munich, but nothing beats that (tonight)."

"Their support is fantastic, it keeps them going, gave them energy to keep pressing the ball. Celtic were very industrious and not easy to break down."

Despite the draw, United are still joint leaders or Group E level on eight points with Villareal, who drew at Aalborg of Denmark on Wednesday.