While their league form as taken a dip, Newcastle have been enjoying success in Europe and have already qualified for the Europa League round of 32.
However, Martinez does not think competing in an extra tournament is to blame for their five-game winless run in the Barclays Premier League.
"I've seen Newcastle play this season, it was the game against Liverpool (where they drew 1-1), and they never lost their competitive edge," Martinez said.
"They are a very difficult team to play against and are a team of real quality and up front they can score with ease.
"I don't think the threat of the team has been touched at all. The negative result is something that happens to everyone in this league and we are going to have to be focused and show good concentration to face this Newcastle side on Monday.
"From our point of view we can't wait to get out on a football pitch and get the positive result I think our level of performance would allow us to have."