Steve McClaren's side beat West Bromwich Albion 1-0 on Saturday.
The Magpies went into the game sitting in the bottom three, with a 3-0 loss to Everton in midweek having dampened spirits after a busy January transfer window.
However, they returned to winning ways on Saturday as a goal from Mitrovic saw them to a 1-0 win over Baggies, a result which took them out of the bottom three and a point clear of Norwich City, who lost to Aston Villa.
And Mitrovic says they will definitely stay up because of the quality they have in their side.
“That was a very important result for us,” he told BBC Sport.
“We tried to press high from the first minute, and we got the first goal. I thought we should have scored more goals, but 1-0 is not a bad result.”
"We will stay up, of course we will. We have quality - I know we will be safe."
The Magpies will be hoping that is certainly the case, and they will be equally keen to see Mitrovic play a big part in any potential escape from relegation.
His goal against West Brom was only his fifth in the league, with him and his fellow strikers having struggled to score goals in general this season.
The goal against West Brom proved to be a crucial and timely one then, and they will be hoping it is the first of many in the 13 games remaining of this season.