Sir Alex Ferguson has earmarked German champions Borussia Dortmund as the dark horse in this year's Champions League campaign.

Dortmund finished at the top of Group D, ahead of Real Madrid and Manchester City, without losing a game. They may be 15 points behind Bayern Munich in the Bundesliga but Ferguson feels their poor domestic season means they will now be completely focused on winning the European title.

Ferguson feels Dortmund are the dark horse this year

"The dark horse is definitely Dortmund. I don't think they are paying too much attention to the league. Their concentration is on the European Cup and their European form has been very good," the Manchester United manager told Fifa.

Jurgen Klopp's team's last-16 tie with Ukrainian champions Shakhtar Donetsk is poised at 2-2, ahead of the second leg in Dortmund.

Meanwhile, Ferguson also identified a rejuvenated AC Milan side, who hold a shock 2-0 first leg lead over Barcelona, and Bayern - who have twice been runners-up in the past three seasons - as potential winners.

"It is a very open tournament. I fancied Milan [against Barcelona]. Over the last few years they have played Barcelona quite a few times but they have never been steamrollered. They have always been tight games. I look at the AC Milan team now and they are all young lads in the team apart from [captain Massimo] Ambrosini," Ferguson said.

"Bayern have always had capable and confident teams. Last year they should have won the final and have added to their squad this year with Javi Martinez and Mario Mandzukic up front. They are going to have a chance," the Scot said.

Ferguson is hopeful of seeing off Jose Mourinho's Real Madrid

Ferguson believes United will also become a top contender for European glory, if they make it to the quarter final. To do so, however, they will have to find a way past Madrid. The tie is level at 1-1, following the first leg at the Bernabeu.

"In addition you have got the two Spanish teams so it is a really tough competition this year. But if we qualify against Madrid we will definitely come into the same bracket," the 71-year-old claimed.