Zinedine Zidane's side will now play Brazilian side Gremio in Saturday's final.
Al Jazira's Brazilian forward Romarinho scores.
Before falling behind Madrid had two first-half goals ruled out for infringements.
The Spanish giants scraped past their UAE opponents 2-1 thanks to a late goal - the substitute scoring with his first touch after coming on in place of Karim Benzema. Bale took a feed from the right side from forward Lucas Vazquez.
Bale said: "It is great to get a goal".
European clubs have made it to the Club World Cup final every time since the competition's new format started in 2005, winning nine out of the last 10 titles.
The strike was also Ronaldo's 31st goal in worldwide competitions in 2017, with 20 of those coming for Real and another 11 with Portugal.
However, those claims fell on deaf ears and Madrid instantly broke up the other end to open the scoring. That particular strike at home to Borussia Dortmund also took him to 114 career goals in 146 Champions League games - another of his personal records, and came just 24 hours before he matched Messi by picking up a joint record fifth Ballon D'Or award. I don't really want to go into details, because it happened the way it happened, and we don't have to worry about those details.
Madrid defenders were unable to clear a ball near midfield, and allowed Romarinho to enter the area and send a low shot into the far corner. Mbark Boussoufa scored, but a video review later showed that he was just offside when he received the pass from his teammate.
"We wanted to win it, we knew [Gremio] were good, but Madrid have never won five trophies in a year and Zidane told us that we must drain our batteries, and we are deserved winners".
Benzema should then have put his team ahead but first he shot instead of picking out Ronaldo and then hit the post.