Stefan Scougall says the Blades will be going all out for victory in Sunday's FA Cup third round tie against QPR at Loftus Road, kick-off 1pm.
The diminutive Scotsman thinks the R's will be wary of the Blades, who beat Aston Villa and Fulham en route to the the semi-finals of the competition last season, before beating West Ham and Southampton in the Capital One Cup this term, to secure a last four clash with Tottenham Hotspur.
Although Scougall can't pinpoint why the Blades have been so successful in cup competitions under Nigel Clough, he thinks Harry Redknapp will be more wary of United given their ever increasing reputation for causing cup shocks.
Looking ahead to the weekend, the 22-year-old said: "We seem to be a team suited to cup football for some reason, although we can't really put our finger on why because we prepare exactly the same as we do for league matches.
"But the fact is we have caused a number of surprises in recent months, nobody would ever expect a League One team to be in the semi-finals of a domestic cup competition, but we will have been in both in less than 12 months, which is a fantastic achievement.
"That will count for nothing when we step on to the pitch in London on Sunday though and I am sure QPR will be keen to make sure we don't beat them, because Premiership teams don't expect to be losing to clubs two divisions below them.
"What we will do though is look to stay in the game for as long as possible and if we can frustrate the opposition, especially with them being at home, as we have done in the past, then who knows what might happen again."
Scougall continued: "We seem to play with that bit more freedom in cup matches and hopefully a positive result against QPR will kick-start our league form and prepare us for two legs against Spurs.
"It is going to be a busy but exciting month and hopefully the magic of the FA Cup will once again be with us in 2015."