Stephen Dobbie opened the scoring on the half hour with a free-kick whipped in at pace from an acute angle which evaded everyone.
Blades defender Shane Lowry then saw red for handling Scott Sinclair’s goalbound effort on the line, with the England Under-21 winger stepping up to score his 24th goal of the season from the spot.
Dobbie then grabbed his second of the afternoon and Leon Britton rounded matters off late on against his former club, to leave a youthful and relegated United second from bottom in the final standings on goal difference.
Sheffield United manager Micky Adams, only appointed in late December, said: “I have a meeting with the club’s owners next week but I can’t prejudge it.
“I don’t know what will happen but I want to carry on. Absolutely. But (chairman) Mr (Kevin) McCabe will set the agenda.
“We had a lot of players from the youth team in the side today and I’m not sure if that is the right thing to do at this moment in time.
“There are four good teams in the play-offs. Swansea are a good team but I know they will not change their style of play.”
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