Casemiro came out on top, despite being withdrawn in the 75th minute for Manuel Ugarte, after registering a goal and an assist.
It was his header that opened the scoring, from Bruno Fernandes's free-kick, and a cheeky no-look pass freed Cunha for our second effort of the afternoon.
Accomplished in midfield, his display drew adulation from the crowd in the first home match since he announced he is leaving Old Trafford at the end of the season.
After picking up a yellow card for a foul on Emile Smith Rowe, he was withdrawn by Carrick and received a standing ovation, when heading to the dugout.