Hargreaves produced an impressive performance in his return to action last week, his first outing at any level since United's Premier League draw at Chelsea in Sept 2008.
Related ArticlesManchester United freeze ticket pricesKlinsmann backs Rooney for European accoladePremier League predictionsGarrido: Tevez is Man City's RooneyRibery fit to face United in Champions LeagueSport on televisionBut while the England international insists he is determined to rediscover the form that prompted United to invest £19m to lure him from Bayern Munich in 2007, Hargreaves admits he is still some distance from being pain-free.
He said: 'I wouldn't say that I am pain-free. The surgery did its job, but I am still in the process of getting come injections to try to manage the pain.
'The pain is difficult to describe. I wouldn't wish it on anyone. It's just pain. During my first season (at United) I had the pain, but I was able to play through it.
'My tendon is significantly better than it was, but there is still a bit of pain that comes with. Whether that is through overloading in training or the operation, it's hard to gauge really.
'I have been pretty patient with it so I'm just looking forward to the day I can just explode on the pitch. I would love that.
'But it's about training, getting these injections and trying to go forward from here. I have played my first game now, though, so hopefully I will go on from here.
'For me, it's very much unfinished business. I'm 29, but hopefully I have a lot of time left in football and, ideally, I want to play for another eight or nine years.'
Franz Beckenbauer, Bayern Munich's honorary president, has claims Wayne Rooney is capable of winning the World Cup for England.
Beckenbauer said: 'Rooney is doing an absolutely fantastic job for Manchester United and I must tell you that we at Bayern will fear him when we play United in the Champions League.
"He is a brilliant player who is playing better than ever. It is not easy to score 33 goals for your club in England, or anywhere else, and if he continues scoring like that and playing like that he can win the World Cup for England.'