The Ghana international was on target as Newcastle defeated Preston North End 4-1 on Monday to make qualification to the English Premier League certain
With two games remaining Newcastle have 88 points and are trailing leaders Brighton and Hove Albion by four points and it looks like winning the championship is a tall order, but they have already booked a place in next season's Premier League.
Ayoze Perez broke the deadlock of the game in the 7th minute for Newcastle, before Jordan Hugill cancelled out the lead for Preston North End in the 27th minute.
But Christian Atsu restored Newcastle's lead in the 45th minute- Newcastle broke at pace with Isaac Hayden and his ball to Mitrovic was in turn rolled into the path of Atsu who tucked home from close range.
Before Matt Ritchie registered his name on the score sheet with the third goal in 65th minute and Richie completed the onslaught in the 82nd minute.