Lukaku came off the bench to score the final goal in Albion's 3-0 home win over Brendan Rodgers' side in the opening Barclays Premier League clash of the campaign.
The 19-year-old is aware the Reds, the holders of the trophy, will be seeking revenge and also a much-needed lift after Sunday's home defeat by Manchester United left them in the Barclays Premier League's bottom three.
But Lukaku is confident the Baggies, lying fourth in the table, can harness their league form to a successful run in the knockout competition.
Lukaku said: "To beat them in the league was a big achievement for us but we know Liverpool will want revenge.
"We have to be ready. It's going well for us now and we just have to keep both our feet on the ground.
"If we want to keep our momentum going, we want to win this game and it would also mean we could go with a clear mind to the derby at Aston Villa [on Sunday].
"Chelsea have done well in the league and the cups and I feel we can do both here. The Capital One Cup is also the quickest way to gain a European spot.
"If the team wants to play in Europe next season, we have to win the next game [to keep that hope alive]."
Lukaku's strike partner, Shane Long, has warned Albion to expect to face a Liverpool side brimming with talent - even if Rodgers opts to ring the changes.
He said: "Cup games are brilliant. It gives the so-called fringe players a chance.
"You always want to face the big teams and we have got Liverpool at home - and hope we can keep the winning feeling going.
"They've got strength in depth. They played Young Boys in the Europa League with a much-changed side last week and won.
"They could have fallen away when they went 3-2 down but came back and won 5-3. It shows the quality they have in depth.
"That game was a warning they have got strength. It is one of the biggest clubs in the world and they are never going to give you anything easy.
"I'm also sure, as regards the first day of the season result, they will try to show us it was a bit of a fluke."
Albion will again be without striker Peter Odemwingie, who will serve the second game of a three-match ban after his red card against Fulham 11 days ago.
Right-back Steven Reid is expected to be back in contention to face Villa after having an injection in his lower back to ease his recent hamstring problem.