Manchester United's Rio Ferdinand insists that Liverpool striker Fernando Torres remains a potent force, despite criticism of the Spanish star.[LNB] Torres has scored just once this season and he looks the shadow of the player who has bagged over 50 league goals in his previous three campaigns at Anfield.[LNB]But Ferdinand, who will line up against Torres at Old Trafford on Sunday, cannot fathom why the Spaniard is being criticised so much, and insists he is still a world-class striker.[LNB]"I heard the pundits hammering Torres the other night," said Ferdinand. [LNB]"He's been injured for a long period of time and is just on his way back. You can't expect him to be the same straight away.[LNB]"People jump on the bandwagon, but players get injuries. Torres is a great player and he's proved that to everybody.[LNB]"Two months ago everyone was saying what a world-class player he is and how he was one of the best strikers in the world, so to become a bad player overnight just doesn't happen.[LNB]"I'm under no illusions that I'll be coming up against a top-class player. You would expect him to produce a world-class performance. But I'll be going into the game with no apprehension.[LNB]"You never look back. If you did, you wouldn't be a top player. You have to look forward and just think about the game you're playing that day. It's pointless thinking 'I should have done this or that'. It's in the past.[LNB]"Liverpool is a big match for the fans. It's one they look forward to most. If there's anything to galvanise the local people and the team, it's a game against Liverpool. It's always testy and fiery."[LNB]Ferdinand himself returned to action in the goalless Champions League draw with Rangers in midweek and he cannot wait to face Torres and co.[LNB]"It's just nice to be back," said Ferdinand. "It's been a long wait and hopefully that's all over now.[LNB]"That's why I've been working so hard in the gym and on the training ground and stuff, to make sure that when I did come back this time it wouldn't be for one or two games, but for a sustained period.[LNB]"It's been frustrating, yes. Injury-wise, I think I had a good run for 10 years or so, but it's been a bit stop-start these past two years, especially with the last injury.[LNB]"The habit of a footballer is to always go out and play, regardless of little niggles and I probably didn't realise how serious the injury was, so it might have been a blessing in disguise."