The Reds have now just one win in their last four league fixtures, and they have dropped down to the seventh spot in the league table.
Wijnaldum says that the Merseysiders deserved to win at St James' Park, but they were made to pay for wasting their chances.
"We didn't score the chances we had and that makes it frustrating, because I think we deserved to win," the midfielder told the club's website.
"We gave two chances away – one was the goal and the other was in the second half from a set-piece. We had clear chances, good opportunities to score a goal but unfortunately, we didn't take them.
"We are unlucky at this moment. But if we score the chances we have, those things [the Newcastle equaliser] can happen and at the end nobody will speak about it again.
"Now, because we didn't score the chances we had and we conceded one where we were not concentrated enough, everyone will talk about the goal they scored."