Peter Houston believes Celtic are strong favourites to win a place in the Scottish Cup semi-finals.
But the Dundee United boss insists his team can upset the odds if everything falls into place for them. Celtic will travel to Tannadice on the back of a long unbeaten run and most people expect them to win a treble this season, being so far in front in the SPL and also in the League Cup final.
But United, who beat Rangers in the last round, away is not the draw Celtic would have chosen and Houston intends to make things difficult. United won the cup two seasons ago and retain a nucleus of players who lifted the trophy at Hampden. Houston said: "We are big underdogs for this game, Celtic will always be favourites to beat Dundee United."
He added: "The big thing for us is that we try our hardest and I believe if you do that then maybe a wee bit of luck will come to you. We have had that in the last wee while so hopefully we can get a bit more. We are scoring goals and keeping clean sheets - hopefully we've kept some for Sunday.
"The Scottish Cup brings the best out of the fans here and I'd love the players to put a show on for them. We won the cup in 2010, there's only three or four who started at Hampden left and another couple who missed out. So we still have guys who remember it and the young lads were around the place.
"That was a great achievement that season and I hope the experience stands us in good stead."
Houston has been impressed by Celtic's resurgence under Neil Lennon this season, especially as they were lagging 15 points behind in the title race at one stage. But the United boss reckons their early season form was simply down to needing new players to gel so he is not surprised they have kicked on.
He said: "Neil was maybe finding out what his best team was at the start of the season, it takes time. You get judged by the players you bring in and the guys Celtic signed have been doing the job. They have a really strong pool so can make plenty of changes. I have watched them several times lately, they are strong, dogged and pass the ball really well.
"They are a top side so we know how difficult it's going to be. They have quality strikers, Gary Hooper and Anthony Stokes have scored a lot of goals this season and they still have the likes of Samaras too."
United will be without Danny Swanson for Sunday's game but otherwise have a clean bill of health. Houston said: "Danny has not done enough to be involved. He is training but it is too early for him. The squad will be along similar lines to the past few weeks."