Los Blancos were dumped out of the Copa del Rey by Leganes on Wednesday to heap yet more pressure on coach Zinedine Zidane.
The 19-point chasm which separates the reigning La Liga champions and league leaders Barcelona means the only realistic source of silverware is in Europe.
And Ronaldo insists the Champions League is a big priority now with Real needing to navigate past Ligue 1 giants Paris Saint-Germain in the last 16.
Speaking to Chinese outlet Doonqiudi after being voted their Footballer of the Year, the 32-year-old said: “If we can win the Champions League at the end of the year, it will be an incredible year.
“We haven’t started well in La Liga and we are disappointed, nobody is happy about that.
“But now we must work hard for the Champions League because it’s the most important trophy for us.
“It will be difficult in La Liga, but we can’t give up, even if we have dropped many points since the start of the season. We have to keep working.”
The individual honour from Doonqiudi recognised a stellar 2017 for the Portuguese superstar as he inspired both Spanish and European glory.
However, the troubling 2017/18 campaign for Madrid has been mirrored by Ronaldo’s poor domestic form and it is made all the worse by Barcelona rival Lionel Messi’s sparkling displays in Spain.
The Argentine will surely compete to move ahead of Ronaldo in the Ballon d’Or trophy hunt in 2018 with the pair both on five.
But while the Madrid spearhead has some catching up to do, he says individual prizes are not his motivation.
“I’m not obsessed with that because I didn’t even expect to win the five that I have won,” Ronaldo added.
“It is good, though, and between myself and Messi, we have shared the Ballon d’Or for the last 10 years.”
Failures for Madrid could be papered up by a good run at this summer’s World Cup with Ronaldo leading his country at the tournament in Russia.
And he is adamant Portugal can be competitive with the possibility of springing a surprise as they did to win Euro 2016.
“Germany, Spain, Brazil, France and Argentina are going to be the favourites,” said Ronaldo who will lead Portugal into a group with Spain in Russia.
“Despite the fact that Portugal won’t be included among the favourites, we always compete and will do so again.”
New signing Alexis Sanchez will start Manchester United’s FA Cup fourth-round clash at Yeovil on Friday night.
The Chile striker swapped Arsenal for Old Trafford on Monday and his debut for the Red Devils will come at the home of the League Two side.
There is also a first appearance since September for Michael Carrick, wearing the captain’s armband after taking time out to deal with a heart complaint.