United head to Humberside in a strong position but wary of the treat posed by a Hull side rapidly improving under Marco Silva.
Goals from Juan Mata and Marouane Fellaini put the Reds in the driving seat in the first leg at Old Trafford a fortnight ago.
That should be a sufficient enough advantage to take us to Wembley, but despite defeat Hull impressed for long periods and were also unlucky in their 2-0 defeat at Chelsea at the weekend.
There are no new injury concerns for the Reds but Eric Bailly - on his way back after the Ivory Coast's early AFCON exit - will not return in time.
Marcos Rojo is expected to recover from the illness that saw him miss the Stoke game but the injury hit hosts have seven players on the sidelines.
Ryan Mason is recovering from his nasty skull fracture and faces a lengthy absence and Curtis Davies is also out.
Robert Snodgrass, subject of a £10 million bid from Burnley will not feature but loanee Lazar Markovic, formerly of Liverpool, could be included.
Silva's side - currently second bottom in the table - visit Old Trafford in the Premier League next Wednesday for our third meeting in as many weeks (and fourth in total this campaign).
Marcus Rashford's last-gasp goal secured victory for United in our previous encounter at the KCOM in the league in August.
Despite his side's commanding aggregate lead, United manager Jose said that there is no room for complacency.
"Hull played very well against us both times we have played them this season, and they were very good against Chelsea, too.
"So I think they are in a good situation and we cannot underestimate them.
"Marco is a very talented coach, he has a difficult job in hand but I knew that the team would really improve.
"It is a big fight for them with five, six, seven teams for relegation but a good, very good, coach.
"It's nice to win a competition and that is what we want to do, but I don't think it's crucial to do well after that - we go competition by competition and match by match.
"It is going to be difficult but we can approach this game like we do the others and I hope we can get to Wembley."
Liverpool host Southampton tonight (Wednesday) in the other semi final at Anfield with Claude Puel's side defending a slender advantage.
Form guide: Hull D L W L L L United W W W W D D
Match odds: Hull 23/4 Draw 7/4 United 5/1
Referee: Jon Moss