Ronaldo has been linked with a move to Atleti after making clear his desire to leave United in this transfer window.
The La Liga club has since insisted its business is finished and Ronaldo is due to play for United in Monday's (AEST) friendly with Rayo Vallecano.
Sunday's (AEST) warm-up ahead of the start of the new season next weekend was largely light on incident until the closing stages.
Anthony Martial and Anthony Elanga spurned promising opportunities for the Red Devils in the first half.
Saul Niguez failed to hit the target with a header and Harry Maguire did the same at the other end in the second half.
The game looked destined to end goalless until substitute Joao Felix drilled a low shot beyond David de Gea before Fred was dismissed in stoppage-time after receiving a second yellow card.