Both Isak and Willock began Wednesday's thumping 5-1 win at West Ham on the bench, with the former netting after head coach Eddie Howe brought him on.
And now Howe has opted to bring the duo back into his side for United's second of three successive away games as they look to topple the Bees and further boost their hopes of a top four finish.
Nick Pope starts in goal, with Kieran Trippier, Fabian Schär, Sven Botman and Dan Burn continuing in defence.
In midfield, Bruno Guimarães lines up in the middle, with Sean Longstaff to his right and Willock to his left.
And Sweden frontman Isak will lead the line for the Magpies, with Jacob Murphy and Joelinton providing support from the right and left flanks respectively.
Those two changes mean Callum Wilson drops to the bench, where he is joined by Anthony Gordon, Elliot Anderson and Matt Ritchie. Allan Saint-Maximin, another starter in midweek, is not involved.
There are plenty of defensive reinforcements among the substitutes in the shape of Javier Manquillo, Jamaal Lascelles, Paul Dummett and Matt Targett, while Martin Dúbravka is the backup goalkeeper.
Newcastle United: Nick Pope; Kieran Trippier, Fabian Schär, Sven Botman, Dan Burn; Sean Longstaff, Bruno Guimarães, Joe Willock; Jacob Murphy, Alexander Isak, Joelinton.
Substitutes: Martin Dúbravka, Javier Manquillo, Jamaal Lascelles, Paul Dummett, Matt Targett, Matt Ritchie, Elliot Anderson, Anthony Gordon, Callum Wilson.