Gareth Bale and Nacho Fernandez also scored twice, and Luka Modric added another goal for Madrid as they regained fourth place in the standings, cutting the deficit to Barcelona to a still massive 16 points.
Upon seeing the blood on his face, Ronaldo signalled that he was calling it a day and he went straight down the tunnel to clean himself up.
Benzema didn't find the net himself, but with the French striker on the pitch Real Madrid looked more risky, more fluid.
The club's doctors declared him unable to continue for the remainder of the game even though Real had used their three changes.
Ronaldo's individualistic attitude, his determination to become the most prolific player he can be is what has made him Real Madrid's all-time record goalscorer.
Cristiano Ronaldo has never been a fan of other players' goals.
Though the French team is arguably the best in Europe, perhaps along with Manchester City and Barcelona, some believe that Real Madrid will show again their greatness when facing a highly hard task. "All I know is that players need to rest, especially if they want to arrive at the final stage of the season in top condition". His current one, signed six months ago, runs until 2021. However, Ronaldo is rumored to be upset with his contract and is considering leaving Madrid.
And according to Gianluca Di Marzio, Real Madrid want to respond to Barca's big transfer acquiring the services of Salah's former teammate Coutinho, by attempting to sign Mohamed Salah. "It would have been nice to have stayed on to get the hat trick, but the most important thing is always to get the victory and to try and get some confidence back in the team". However, that still does not explain everything. Yet this season is different, only seven goals and a limited influence, likely to be because his head has been elsewhere and his rapport with his teammates has deteriorated.
Intriguingly, the season started completely differently for both Real and Ronaldo.
So, that is where Manchester United come in. Next summer then? Maybe, it will be a different situation.
Zidane said his "BBC" strike force of Gareth Bale, Cristiano Ronaldo and Karim Benzema were fit to play, though he did not reveal if he would field the trio, who have not started a game together since facing Barcelona in April a year ago.