The Belgian striker expects the Anfield club to be motivated to avenge the 3-0 loss they suffered in the Premier League, earlier this season, when the sides meet in the League Cup
It is just a month since Brendan Rodgers’ side were humbled 3-0 by The Baggies at the Hawthorns on the opening day of the Premier League season.
"To beat them in the league was a big achievement for us but we know Liverpool will want revenge," Lukaku told The Independent.
"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]."
Competition for places up front is fierce at the Hawthorns and summer signing Markus Rosenberg is hoping to start against Liverpool and stake a claim for a permanent place in the starting XI.
"It would be great to start as I played 15 minutes on Saturday and hopefully I will get a chance to start against Liverpool," Rosenberg told West Brom's official website.
"I feel good in training but training is one thing and playing is another. I need more game time."