José Mourinho has warned that Real Madrid can score the goals to knock Manchester United out of the Champions League at Old Trafford, with the Portuguese claiming Sir Alex Ferguson's side have not yet faced any team there with "our attacking quality".

United left the Bernabéu with what may prove to be a vital away goal, having drawn 1-1 after Danny Welbeck's first-half opener was cancelled out by Cristiano Ronaldo's header before the interval.

Yet Mourinho is confident. Madrid's coach, reflecting on a cautious approach from the visiting team, said: "I won't criticise what they did – they got the result they wanted. We can score at Old Trafford. Many teams have done so at Old Trafford and no team with our attacking quality has played there."

Ferguson detailed Wayne Rooney to play on the right as he asked the striker to help Rafael da Silva, the full-back on that flank, shackle the threat of Ronaldo. The manager also played Phil Jones in advance of his more usual central-defensive berth as part of a midfield shield.

Of these tactics, Mourinho was mildly critical. "I don't think, with the British culture, that United will play with all their defenders in their half, as they did here," he said, speaking of the second leg in three weeks' time. "I am expecting a very strong opponent [then] with very good players, but I am confident and 100% sure we can do this. It is 50-50; it is a draw. They scored an away goal and we can do that as well. I like to play first game at home because when you play first game away, the tendency is to be unhappy with the score.

"When you play second game away, you know how you need to approach the game. When we get to Old Trafford we are behind and need to score. If we score, we go ahead, so it is very easy and we know what to do.

"We had enough chances to score more than one. We had the initiative all the game and we played against a team with lots of payers covering their own area. United did their job well. They came here not to concede space and goals and they didn't play to win."

For Ferguson there was contentment at the result. "Before the game we would have taken 1-1, without question," he said. "It is a difficult place to come to – their home record is outstanding."

He disagreed with Mourinho's contention that United had come to defend. "Of course we tried to win it; we had four attacking players in the team," he said of Rooney, Robin van Persie, Welbeck and Shinji Kagawa. "But we sat a bit too deep in the first half and allowed them space. We defended too deep and it was fortunate that David de Gea was excellent. But we kept making chances. And let's hope we don't regret that [not taking them]."

United's manager was lavish in his praise for De Gea. "He made three or four top saves," he said of the goalkeeper. "He has been improving all season. There was one save in the first half which he touched on to the post [from Fábio Coentrão] which was superb. I am pleased for him. He is an Atlético boy playing here in Madrid, but he has done well."

Ferguson agreed with Mourinho that the tie is in the balance. "Yes, I think it is," he said. "It could go either way now. It really depends on who scores the first goal. The team that scores first will have a good chance."

The Scot said United may play differently in the second leg, when a goalless draw would put them through. "We have to look differently as they are a fantastic counterattacking team. At Old Trafford we have to be more positive in terms of selection but we have goals in the team and you must remember that."

For Ronaldo there was no great celebration after his goal against the club where he played from 2003 until joining Real in 2009. "I was in Manchester for six years so tonight was very emotional for me. I scored a goal but I didn't celebrate out of respect. Maybe United are favourites now, maybe not. Anything can happen. Sometimes we are better away than at home – we will see. It will be amazing to play at Old Trafford again after four years."

Mourinho, whose side have all but conceded the Liga title they won last year, is under pressure to claim the Champions League or he could be sacked.

Yet asked if his future depended on the result of this last-16 tie he said: "I have no idea and I am not worried about it. I don't feel any pressure. I work hard, am very serious and am happy with what I do.I have peace of mind and my head is high, but there is no pressure really."