Football | Champions League
Real, United share spoils,Dortmund draw
Shakhtar Donetsk and Dortmund also shared the spoils in a 2-2 draw in Donetsk, but a late goal from Dortmund's Mats Hummels put the Bundesliga champions in the driving seat for the return leg.
United took the lead against Real when Wayne Rooney's corner was headed in by Danny Welbeck in the 20th minute for the away goal manager Sir Alex Ferguson was looking for.
Real's Ronaldo levelled on the half four for his seventh goal in seven matches, rising high for a powerful header after Patrice Evra failed to get off the ground from an Angel Di Maria cross.
Real, who had come close when Fabio Coentrao's shot was touched onto the post by David de Gea in goal, finished the half strongly, and de Gea was also busy in the second half, keeping out a Coentrao effort with his legs on the line in unorthodox fashion.
But Robin van Persie twice went close, first with a fierce shot tipped onto the bar by Diego Lopez, and then, after Real failed to clear, the Dutch striker misconnected with an effort which was cleared off the line by Xabi Alonso.
"We had a couple of chances and if you said we would have left here with a 1-1 at the beginning of it we'd have taken it," van Persie said.
Ronaldo said Real would still have chances against United in what will be a return to Old Trafford for the Portugal striker, who was six years at United.
"It was a tough game. They are a very strong team defensively," he said. "We played better and deserved to score more goals."
Manchester United manager Sir Alex Ferguson said Ronaldo's header for Real's goal was "unbelievable."
"You can't stop that, the leap and the spring to hold himself in the air," he said.
"I think it was difficult for him playing against an old team, and it had a little bit of emotion attached to it because he played for us for six years, but he was still a big threat for them. When he gets the ball you are praying more than anything."
Real Madrid manager Jose Mourinho said the match was no surprise, with United "waiting for a set piece or counter attack."
"The result is open and if you ask me for a percentage I don't change," he said. "It's still 50-50. We can score more than one goal at Old Trafford.".
In Donetsk, a minute's silence was held before kick-off following the crash of a passenger jet during landing near Donetsk earlier in the day with several fatalities. Many passengers were believed to be travelling to the match.
Donetsk, aiming to reach the quarterfinals for only the second time went in front against 1997 European champions Dortmund when captain Darijo Srna's direct free-kick from 22 metres out beat Roman Weidenfeller in goal.
Dortmund had struck the bar with a Hummels header, and the visitors deserved their equalizer when Robert Lewandowski's miskick took two Donetsk defenders out, leaving the Poland striker free to plant the ball into the corner of goal.
But it was the home side who got back in front when in the 68th minute substitute Douglas Costa, on for just six minutes, got on the end of a long ball from Yarsolav Rakytskyy to hook the ball in.
Dortmund snatched a draw though when Hummels headed in a Marcel Schmelzer corner three minutes from time to put the Bundesliga side in a good position to reach the last eight.
"It was good. We played well, with just two or three moments when were weren't concentrated," Dortmund coach Juergen Klopp said.
"Even 2-1 wouldn't have been a bad result. At home we can play a bit of football."
With Juventus 3-0 winners at Celtic, and Paris St Germain earning a 2-1 victory at Valencia Tuesday, none of the home sides of the last-16 matches so far have managed to win. The remaining four first-leg matches will be played next week.
The return legs are on March 5 and 6, and March 12 and 13.