The 49-year-old former Blancos striker says the Champions League tie is finely balance, and added that Cristiano Ronaldo's headed equaliser was "very beautiful"
The 49-year-old believes his former side could have led at half-time, following a dominant opening 45 minutes from Jose Mourinho's team.
"The first half was ours and we conceded from a set-piece. We had to leave with an advantage on the scoreboard. The team did a great physical effort in the first half," he told Real Madrid's official website.
The former Madrid and Spain star also praised the performance of Sir Alex Ferguson's side, adding: "They defended well.
"Manchester United are a good team; they have a competitive spirit and great players."
Butragueno also praised Cristiano Ronaldo's stunning header, saying: "It was a great goal and a great example of how to get up. It was a very good - and accurate, something of great beauty.
"I know that there will be a great reception (when he returns to Old Trafford)."
The second leg takes place on Tuesday, March 5.