Danny Welbeck's headed opener gave United the lead in their last 16 UEFA Champions League first leg in the Bernabeu and, while Cristiano Ronaldo equalised, Ferguson was content enough.
"There were a lot of incidents in the match," Ferguson told Sky Sports. "Chances at both ends. David de Gea has made three or four fantastic saves but we have missed some good chances ourselves.
"Their goalkeeper has made a really good save in the last minute and a good save from Van Persie which hit the bar. It was a really interesting game.
"The disappointing thing for me was that in the first half we sat off them. They got a lot of play on the edge of our box. It's not healthy that. It's not good to watch and it was unlike us.
"But we changed it around after the break and put Danny Welbeck up top on [Xabi] Alonso and that made a great difference. We had a good start to the second half.
"In all we've created a lot of chances in the match and [played] some good attacking football at times but not had the possession we should have had. I think they won the possession without question.
"But they're at home, it's a difficult place to come to and we're pleased with a result that takes us back to Old Trafford with a great chance."
Ferguson admitted he questioned the defending of Patrice Evra who was left flat-footed for Ronaldo's towering header but later decided the goal was virtually unstoppable.
"What a header," he said. "Unbelievable. You can't stop that. I came in at half-time and asked Patrice why he wasn't challenging for that but when I saw the replay I wondered what I was talking about.
"It was maybe difficult for Cristiano playing against us - his old team - because there were a lot of emotions attached to it as he was with us for six years. But he's still a big threat for them. When he gets the ball you're praying more than anything."
Asked how the tie stands now, Ferguson said: "It's very open. I think we'll score at Old Trafford but we know they are going to be a tremendous counter-attacking team so we've got a big job on our hands. But it's definitely within our grasp."
The manager was full of praise for Welbeck who some saw as a surprise selection. "He was marvellous," said Ferguson. "It is a pity he got cramp at the end of game, but he worked so hard.
"It was only his second goal of season. We expected more, but he is young. They found it difficult to handle him."
It was also a night to remember for goalkeeper de Gea, who has found himself under so much scrutiny recently.
"De Gea was excellent," Ferguson said. "He made three or four top saves. He has been improving all season.
"There was one save in the first half which he touched onto the post (from Coentrao) which was superb.
"I am pleased for him. He is an Atletico boy playing here in Madrid, but he has done well."
Ferguson revealed he left out skipper Nemanja Vidic as a direct consequence of United's Premier League encounter with Everton being shifted to last Sunday.
"If we had played on the Saturday, the extra day would have suited me, but he plays one game every eight or nine days and still has to manage his comeback from injury," said Ferguson.
"Rio is exactly the same, and the type of game on Sunday suited Vidic more."