The England striker told Sky Sports News: "We always believe. We believe we can go on and win the league. We have been in this position before and gone on to win titles so there is no reason why we cannot do it again. We are hitting form at the right time.
"If we can continue that and get to Christmas within touching distance, or maybe even at the top, we will be in a great position.
"We are starting to adjust to the training and the new ideas from the manager. We are playing a bit better and have been getting good results. Overall, we are in a good place. I am sure if we can win on Sunday it will make us even stronger and give us that belief that we can go on."
United have not lost in their last four Premier League matches.