There's all the talk of the physical and emotional wear and tear from all the drama with the Libertadores final, but River Plate had 10 days to travel and train and of course, rest. Al Ain is no powerhouse; at one point it was down 3-0 to a team loaded with amateurs. But credit to Al Ain to playing without fear (and credit to Caio, born in Brazil, for his amazing play in which he left much of River's defense in the dust with his speed as he scored the equalizer for 2-2). River did show hunger and grit in coming back very quickly from being down 0-1 to 2-1, but the responsibility for failing to advance against a notably lesser side is squarely on its shoulders. As a poster said in the CWC forum, "after all that trouble River is going to blow this?" With this result, a pattern has held: since the 2005 inception of the FIFA Club World Cup, no teams other than Brazilian winners of the Libertadores have advanced to the final and won the trophy by defeating the Champions' League champion. Let's see what 2019 brings.
It's funny how soccer consistently gives fans ways to "get back" at fans of opposing teams. You Boca fans will have to endure the trash talk by River fans concerning the 2018 Libertadores final for eternity, but you will then be able to tell them they are the first Argentine team to lose in the CWC semifinals.