It kept them nine points in front of second-place Crewe and ensured spirits will be high going into the re-arranged game at Gresty Road.
Liddell, who now has 14 goals league goals to his name this season, said: "It wasn't the best of games at Wycombe but the important thing was that we won.
"We now go to Crewe, and if we can win there, it will dent their morale.
"There would be a big points difference then, we're talking 12 points, so we will be going for it.
"It will be red hot down there, a lot different then on Saturday when with no disrespect to Wycombe, the atmosphere was nil.
"Crewe will be wanting to topple us and get closer to us in the table, but hopefully we can come out with a result.
"Getting promotion isn't an easy job despite us having a nine-point lead at the top.
"People expect us to be promoted because we're Wigan, but that is people on the outside.
"Those on the inside of the club know it is hard job, and I have been here a few years now and have seen us mess it up before."
Latics manager Paul Jewell said: "In the first half we were smashing but in the second we weren't as good to be perfectly honest.
"The game was a bit flat, the atmosphere was flat and we got lulled into that in the second half.
"In the first half, the only criticism I had was that we didn't make their keeper make enough saves.
"We had a lot of the ball, played some great football, but never really tested their keeper.
"Too many shots were going over the bar and we have to be more ruthless.
"But saying that, it is another away win and another clean sheet so I've got to be pleased. Looking at the goals, Lee's header took a bit of a deflection, but it was scant reward for all our possession before half-time.
"As for the penalty, some you get and you don't, and Andy struck it in great."
Missing from the line-up at Wycombe was Peter Kennedy who went down with chickenpox late last week, the virus hitting him hard.
Jewell said: "Peter is covered in spots, he's not a pleasant sight and he has not been very well with it either.
"We all wish him well for a speedy recovery but I don't know at the moment how long he'll be out.
"Steve McMillan came in for him and did very well."