Lions have to defend their pride against other male lions that fight back. Usual tiger prey; deer don't fight back. Lions have more practice fighting bigger, stronger animals; water buffalo, wilderbeast, other lions etc. Lion manes protect from claws and bites.
Trey Tigers also fight other tigers over territory and they hunt the same kinds of animals as lions or animals that are of comparable size to what lions hunt, alone without help. If you look up what kinds of animals tigers hunt, you will see that your statement is false. Lions do it in a group so to say that they have more practice fighting bigger, stronger animals doesn't really make any sense from a logical standpoint. It would make more sense to say that I would get more experience fighting alone then I would if I took down the same opponent with a group of other people helping me or animals in this instance.