With Arsenal sitting pretty in fourth place at kick-off, these two teams knew how vital a victory was to their Champions League dreams and Ronaldo set United off to an ideal start.
Taking aim from all of 30 yards, the veteran striker – back in the team after a hip issue kept him out the derby last weekend – fired a stinging shot that gave Hugo Lloris no chance and nestled in the top corner.
Spurs never looked out of the game however, and Eric Dier had a header cleared off the line before they got their leveller. Dejan Kuluseveski’s smart run drew a handball out of Alex Telles and Harry Kane buried the penalty.
That goal came on 35 minutes but United were back ahead only moments later, as Jadon Sancho sprang the offside trap to tee up Ronaldo for a simpler second.
Son Heung-min missed a chance to level the scores again on the hour mark as the game became scrappy and low on quality.
Typically, the equaliser came from a mistake as Harry Maguire slid in on Sergio Reguilon’s cross, bound for the probably-offside Cristian Romero, and put the ball into his own net.
But this was one of those days when there was simply no denying Ronaldo, who rose highest from a corner in the 81st minute to head home his third goal of the afternoon – earning United all three points.