Centre back Clark comes back into the side in place of the injured captain Jamaal Lascelles, while winger Murphy will also line up at Old Trafford, having not started a game since the 1-0 win over Swansea City in September.
Those are the only two changes Benítez has made to his team from the 1-0 defeat to Bournemouth prior to the international break, with Rob Elliot once again starting in goal.
DeAndre Yedlin, Florian Lejeune, Clark and Javier Manquillo make up the back four, with Matt Ritchie starting on the right-hand side of midfield and Murphy – in for the injured Christian Atsu – starting on the left.
In the middle of the park, Jonjo Shelvey will start alongside Isaac Hayden, while Dwight Gayle will partner Joselu in attack.
Karl Darlow, Jesús Gámez and Chancel Mbemba are on the bench, along with Mohamed Diamé.
And Rolando Aarons, Ayoze Pérez and Aleksandar Mitrovic are also available for the Magpies manager to call upon.
Newcastle United (4-4-2): Rob Elliot; DeAndre Yedlin, Florian Lejeune, Ciaran Clark, Javier Manquillo; Matt Ritchie, Jonjo Shelvey, Isaac Hayden, Jacob Murphy; Dwight Gayle, Joselu.
Substitutes: Karl Darlow, Jesús Gámez, Chancel Mbemba, Mohamed Diamé, Rolando Aarons, Ayoze Pérez, Aleksandar Mitrovic.