The Red Devils boss criticised his team's performance after they edged to a slender win over Turkish champions Galatasaray at Old Trafford thanks to Michael Carrick's goal
A seventh minute strike from Michael Carrick proved to be sufficient to win United all three points. However, the Turkish champions had a number of chances to get back into the contest and Ferguson believes that the Red Devils were slightly fortunate to have come away from the game with the victory.
He told Sky Sports: "I think we expected a tough game, Galatasaray have got a lot of experience in their team and the first half we kept giving the ball away and they counter attacked very well from that.
"It was a lack of concentration at times. It's unusual for us, it's unusual for us to be as frivolous on the ball as that. In the second half we did much better in that respect.
"I was happy with the second half, we were more solid, had better concentration and sorted out things really well."
Despite the improvement, the Scot bemoaned his side's wasteful nature from spot-kicks after Nani saw his effort saved by Fernando Muslera, making it two missed penalties in the last two competitive games.
He said: "I don't want a penalty! It knocks you back, you miss a penalty it knocks you back. Like Saturday and today.
"It was a great opportunity to go 2-0 up just before half-time. You miss it and start to worry about losing a goal then."
In spite of this minor setback, Ferguson was pleased to have witnessed his side take maximum points following a dismal campaign in the competition last term.
He added: "Second half we were much more solid at the back, they never made any chances and all the chances fell to us, we could have scored four or five in the second half.
"It was a good opening game, a real good European game, they were very confident in their play and possession, you get that in these European teams, no problem, you just have to be patient with your possession and make it count.
"We missed the chances we did in the second half, we kept ourselves on the edge really. I think to get the three points in the first game is a bonus really. If you go back to last season we got a point at Benfica, so three points are really important."