Just had a look at what Ferguson had to say about Rafa and I found his digs quite pathetic tbh. To compare Rafa's time as Liverpool manager to Di Matteo's time at Chelsea is petty and quite bitter in the extreme. You never saw a more average Liverpool team? Really? That same team hammered you 4-1 in your own back yard.
It clearly still rattles him that no other Liverpool manager ever pushed him closer in the league than Rafa did (and of course, Rafa's win record against him too
Can't fault his criticism of Kenny's handling of the Suarez saga but to be honest, it's easy for him to say that Liverpool should have got rid. I'd love to know what he would have done in a similar situation where you are talking about your one and only world class player, where you're also struggling in the league.