The Croatian striker is well aware that the Barclays Premier League giants are favourites, not only to win Tuesday's opener, but to top a group that also includes Valencia and Turkish champions Bursaspor.
But he pointed out that Rangers had been firm favourites to cruise to victory against Hamilton in the Clydesdale Bank Premier League and needed to battle to the final minute to find the goal that secured the win at New Douglas Park yesterday.
Wide open: Jelavic is confident his side can take points at Old Trafford
And, as far as Jelavic is concerned, there is no reason why Rangers cannot pose problems for their glamorous hosts if they catch United on a night when they are not on top form.
'I think we have a chance,' he said. 'Manchester United is a big team but, in our game, they were 100% and we were a little down and thought it would be easy. Maybe this could also happen in the Champions League.
'You never know. Maybe if we are 100%, we can take some points there.'
Former club Rapid Vienna's progression to the Europa League group stages at the expense of Aston Villa means Jelavic is ineligible to take part in the Champions League this season.
Ruud boy: Rangers were vanquished 3-0 on their last visit to United
However, the big forward - who netted his first goal for Rangers at Hamilton - is confident he will have another crack at the competition next year, while focusing all his efforts on the domestic campaign this time around.
'Of course it's frustrating and all I can do now is watch the game on Tuesday night,' said Jelavic.
'It's difficult. What I can do is stay focused on the SPL and play these games and cup ties.
'It's difficult for me not to play in the Champions League, especially against these big clubs, but I will have my chance next year.'
He added: 'I am happy with my goal. It was nice to score after fiveminutes, it was good for my confidence and I hope I can continue toplay well. I hope I will be better and better and I will score lots ofgoals.'
Struggling: Jelavic was on the scoresheet against Hamilton but looks set to miss Euro clash with United
Jelavic's opener was cancelled out by an own goal from Madjid Bougherra before Kenny Miller came off the bench to rescue the points with his sixth goal in four SPL matches.
'I was sure the goal would come,' said Jelavic. 'I have said before that Kenny only needs a little chance to score a goal and he has shown that again.
'It's always good to score some goals in the games for the confidence and we have players who can score from a little chance and this is good for the team.
'When we came here we knew were the better team and if we had played at 100%, normally three points would have been easy for us.
'But that's football. We didn't play well but we had some luck and sometimes with the big teams you have to have some luck if you're going to take some points.'
As far as Accies boss Billy Reid was concerned, it was a case of same old story against the Old Firm.
He said: 'I'm just gutted for the players. They put in so much effort and did the right things and they deserved a point and came away with nothing.
'There are many games where that has happened against the Old Firm and that's why they are the top teams in Scotland.
'You know when Rangers bring on Kenny Miller that you've got to shut your back door. We didn't do that and that's why we were punished.'
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