Although the Exiles are tenth in Sky Bet League Two, having lost four of their last six games, they have won seven of their last ten at home.
And the U’s caretaker boss expects the hosts to come out with all guns blazing as the visitors look to extend their unbeaten away league record to 17 matches.
“I think they are a good side. I don’t think they are struggling,” said Lewis.
“They haven’t played at home for quite a while, and they are going to be major up for it.
“Apparently, they were really unlucky on Saturday at Hartlepool. The 3-0 score flattered Hartlepool.
“Newport are normally very good at home. They have got a good record there.
“It’s going to be a real tough battle, but we’ll definitely be trying to win the game.”
Under Lewis’s guidance, the U’s are unbeaten in their last five matches, capped by Saturday’s impressive 3-0 home win against Mansfield.
But for Lewis, it is just about concentrating on the challenge of Newport.
He added: “I’m not really thinking about it. This will be the toughest game we have faced all year.
“I know Justin (Edinburgh) is a really good manager and he will have them fired up.
“Wayne Hatswell (ex-U’s defender) is a coach there. He was a competitor and that’s how their team will play. They are attacking and really go for it at home, a little bit like we did on Saturday.”
United have no fresh injury worries, though skipper Jake Wright (leg) and Michael Raynes (hip) are not yet ready to return.
Newport will carry out a precautionary pitch inspection at 1pm as they look to stage their first home game since January 4 when they lost to Northampton Town.
They are without striker Aaron O’Connor (groin) and keepers Lenny Pidgeley (ankle) and Jamie Stephens (groin), so Elliott Parish, on loan from Bristol City, continues in goal.
Newport Co: from Parish, Worley, Naylor, Sandell, Pipe, Chapman, Minshull, Burge, Willmott, Jeffers, Howe, Zebroski, Porter, Jolley, Hughes, Crow, Jackson, Thompson.
Oxford Utd: from Clarke, Bevans, Hunt, Mullins, Newey, Wroe, Rose, Ruffels, Smalley, Kitson, Constable, Connolly, Potter, Williams, Rigg, O’Dowda, Marsh, Davies, Long, Henly.
Match highlights from earlier this season: