The Magpies' latest win - a 2-1 success against Arsenal - was somewhat overshadowed by Sunday's other result - Manchester United 0-1 West Bromwich Albion - which secured the title for Manchester City.
But with the plaudits heading Pep Guardiola's way, after the City boss first championship success in England football, McDermott was quick to divert attention back to another Spaniard, Benitez.
The former Newcastle player and assistant manager posted:
Benitez - whose future has been called into question at various points this season - has led the Magpies to tenth in their first campaign back in the Premier League, having led them to the Championship title last term.
And with a 13-point lead over third-from-bottom Southampton, United's top flight status is all but guaranteed for another year.
Are Rafa's achievements with Newcastle greater than Pep's with Manchester City?