I think the accepted wisdom now is that although anything could happen in individual fights, all things being equal the male Lion will win more often than not despite being outweighed by the largest of Tigers. Male lions spend their entire time patrolling and fighting other lions, often to the death (rarely instant but from grave wounds). Apart from shagging and eating, that is pretty much all they do. They rarely get involved in hunts. Fights with other males are relatively common so they have a lot of experience of it in their lives. The mane of the male lion is larger and thicker to stop other lions getting to the throat area easily.
Tigers are more solitary and both genders are very good at hunting. Confrontations will other tigers are rare and serious incidents rarer still (no females/prides to attack for, just territorial overlaps).
Tigers > Lions for hunting. Lions > Tigers for fighting.
if it's a male lion, then my bet is on the lion because their mane protects their jugular in fights against other lions/enemies. if it's a lioness, then the size and amount of fur a tiger, male or female, has would definitely win them the fight.