The Magpies ended a four-game winless run last time out with a hard-fought 1-0 victory against Manchester United at St James' Park, a result that lifted the hosts into 13th position in the Premier League.
Safety is nowhere near assured for Rafael Benitez's men who are only two points above the relegation zone, especially when the north-east outfit still have Arsenal, Chelsea, Liverpool and Tottenham to face.
Captain Lascelles, who has been a standout performer for Newcastle this season, is feeling optimistic for the rest of the campaign and believes his side will down some of the big guns.
"Lately we haven't been getting what we deserve. But finally we've got three points against a really big team here," he told the Chronicle.
"It's been a good few years since we last beat Man United and we must take confidence from this. It's massive.
"But like I say with these bigger teams they'll have massive players on big wages. They are world-class players but they won't always have the same heart and determination as we have.
"I said before the game against Man United that our hard work and endeavor will get us over the line, and that's exactly what we did."