Their underwhelming domestic season has left manager and club legend Zinedine Zidane under piles of pressure and uncertainty regarding his future in the Spanish capital.
This morning's defeat to fifth-placed Villarreal hasn't helped Zidane's case, and many fans believe five-time Ballon d'Or winner Ronaldo is the root of both his manager's and his club's problems.
The 32-year-old wasted several chances in front of goal during this morning's defeat, fuelling criticism aimed towards the Portugal captain.
Ronaldo's performance this morning was symbolic of how his personal season has turned out thus far.
Although he has met his lofty expectations in the Champions League (he leads the competition's goal scoring charts, netting nine in six appearances), Ronaldo has scored just four goals and assisted only two throughout 13 La Liga matches this season.
Comparatively, long-time rival and Barcelona hero Lionel Messi leads the league with 16 goals in 18 clashes, including one in last month's El Clásico fixture which Real Madrid lost 3-0.
Additionally, the Argentine has set up seven goals, placing him second on the league's assist leaderboard.
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Such dismal figures for the former Manchester United playmaker doesn't bode well for both Real Madrid and Portugal for the remainder of 2018.
The glamour club will need their star man to be in top form next month when they face an imposing PSG outfit - lead by a dangerous front three consisting of Kylian Mbappé, Edinson Cavani, and world record signing Neymar - in the round of 16 stage in the Champions League.
Considering the Champions League may well be their best shot at a major title this season, it would be devastating for Real Madrid should they depart the tournament at such an early stage of the competition, and could well bring an end to Zidane's tenure as the club's manager.
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With the World Cup just six months away, Portugal will need their captain at the peak of his powers if they are to form a substantial run at a first-ever title.
The current European champions could find life difficult in Russia should their most capped player (147 caps) and highest goal scorer (79 goals) fail to fire, especially with traditional foes Spain placed in their group.
For the sake of his manager, his club, his fans, and his country, Ronaldo needs to become more efficient in front of goal and regather the form that saw him claim consecutive Ballon d'Or trophies over the past two seasons sooner rather than later.