Owen has spent most of his time at United on the substitutes bench since joining from Newcastle in the close-season while he strives to reach peak form and fitness.
But the former Liverpool star made himself a hero forever at Old Trafford on Sunday when he came on to break City hearts with a fine finish in the sixth minute of stoppage time to cap a clash Ferguson claimed was the arguably the best derby of all time.
United had led three times through Wayne Rooney and two Darren Fletcher headers, but City hit back through Gareth Barry and two goals from Craig Bellamy, with the Wales striker's second coming in the 90th minute.
"To be fair we noticed in the last two weeks Michael's adjusted to training and has been sharper," Ferguson told Sky Sports.
"Even when he came on against Besiktas, he showed that sharpness.
"We were saying that we were going to have to get him on and get him game time because he's been doing very well.
"I felt the game would be in their box. There was no doubt about that in the last 20 minutes we sensed that and there is no one better than Michael Owen when that happens."
Ferguson has seen more than his fair share of classic matches in his 23-year reign at United but the Scot admitted none had surpassed this encounter.
"What can you say? We've given three goals to them," he said.
"It could have been an embarrassment, 6-0 or 7-0, if we defended our proper way.
"We could have won by a big score but by making mistakes, which was the essence of the game, we probably were in the best derby game of all time," he said.
"What do you choose? Win the best derby game of all time or win 6-0? I'd probably pick 6-0."
Rio Ferdinand made an error for Bellamy's second goal and Ferguson admitted the England defender will be relieved after Owen's winner.