A Jaguar is usually smaller than a tiger so if the jaguar was alone then the tiger would kill the jaguar.
However if the Jaguar was with a few other jaguars and came up against only 1 tiger then the jaguars may be able to overpower the tiger and kill the tiger.
But if the tiger and just one jaguar gets into a fight the tiger would be able to easily overpower the jaguar and the jaguar would be killed by the tiger.
I was once camping in the woods and saw a tiger and a jaguar come up against each other.
The tiger overpowered the jaguar and the jaguar was killed by the tiger.
So if a jaguar comes up against a tiger then it will likely not live unless it runs away from the tiger when possible.