Manchester United face Real Madrid in the second leg of a Champions League knock-out tie at Old Trafford on Tuesday. United legend Gary Neville believes Sir Alex Ferguson's side and the Spanish champions each have a 50:50 chance of making it to the quarter final of the tournament. The Premier League leaders have an away goal advantage after the first leg, at the Santiago Bernabeu, ended 1-1.

Karim Benzema
Real Madrid\'s Benzema is challenged by Manchester United\'s Carrick and Rafael during their Champions match in Madrid. Reuters

"I'll be honest. I've been asked hundreds of times, and I think after thinking it over I have to say that things are 50-50. Both teams rely heavily on their front, for its great potential," Spanish newspaper AS quoted Neville as saying.

Neville believes United need to be cautious about their midweek opponents as Jose Mourinho has twice achieved European glory with his former clubs Porto and Inter Milan.

"Manchester will have to be very careful. Speculation about the future of Mourinho. He won the Champions League with Inter, in Porto. Madrid will win in the extraordinary. Also for the players, which will secure its best in Europe, the 100.1% is mathematically impossible but it is not in football. Anyway, it is risky to leave everything to a competition," he added.

Madrid are not having a great run in the Spanish league as they are third in the La Liga table with 55 points from 26 games, trailing league leaders Barcelona by 13 points. Neville claims winning the Champions League this season could be their main priority after their hope of retaining the league now seems difficult.

"I see that his whole season depends on the Champions League. That can certainly be positive, helps them to concentrate their efforts. But also a pressure element added. If you put a weight on the good and bad of the two teams would be very balanced. Even the fact that the second leg is played at Old Trafford decantarme helps me. I do not hide, but I see them as matched," Neville concluded.

Madrid enter this game in impressive form after defeating arch-rivals Barcelona twice in less than a week; the first being a 3-1 win at Camp Nou in the Copa del Rey semi final and the second a 2-1 victory at the Bernabeu in the league fixture last Saturday.