Manchester United boss Sir Alex Ferguson admits their late draw was a "travesty" for FA Cup opponents West Ham United.

Ferguson's mood was lifted as substitute Robin van Persie showed his immeasurable class in the 90th minute, latching onto Ryan Giggs' sublime pass to slide past Jussi Jaaskelainen and book a yet to be scheduled replay at Old Trafford.

"We want to stay in the competition and have a go at winning it," Sir Alex told MUTV. "We've had some terrible draws over the years and been knocked out early, we don't enjoy that. For us to be losing 2-1 in that game was amazing given the chances we created and the football we played.

"But when you play West Ham you have got to defend your crosses from the set pieces because they are brilliant and the best team in the league at that, but we didn't do it. Twice, from the same position, James Collins scored from the same type of cross from Joe Cole and we lost two goals.

"Really, you could say it was a travesty but they are good at it and you have to admire that part of their game. Given some of the football we played and the chances that we missed, we should have really been home safely."