Gabriel Heinze last night revealed the FA Cup has become a personal "obsession" as he set his sights on winning the Treble with Manchester United.

Argentinian Heinze was injured and missed the 2005 final, when United lost to arch-rivals Arsenal, and is on a one-man mission to win the famous trophy in the first final at the new Wembley.

The next three weeks will define United's season as they pursue a Treble of Champions League, Premiership and FA Cup, and Heinze maintains it is within their grasp.

"It is very tough and we will have to be at our best," he said.

"But this team is very united, together - and that is key to our success."