For 53 long minutes, it looked like being another blank day for United as Ferguson's injury-hit side struggled to make their dominance tell.
"We needed a spark - and Carlos provided it," said Ferguson.
"There were challenges coming in from all angles. But he kept his nerve - which was the right thing to do.
"The second-half performance was absolutely superb. We speeded the game up, and the flow was much better.
"There was excellent interplay between the strikers, and it seems to be coming together.
"While there is still a long way to go, I have a lot of confidence in this squad."