Oz

Siberian Tiger:
Male
7 Years old
840 LBS
105 inches long
4 feet tall at shoulder

Pros:
Fast.
Good jumping ability.
Smarter than bear.
Cons:
Less brute force than bear.
Size disadvantage.
Hide not as thick as bears.

Grizzly Bear:
Male
9 Years old
1200 LBS
4 feet tall at shoulder
9 feet tall on hind legs

Pros:
Powerful blows with front paws.
Size advantage.
Thick, tough to penetrate fur and hide.
Cons:
Not as agile.
Not as fast.
Not as sneaky/smart.

So, Assuming both animals are alpha males. They are both REALLY pissed and hungry/thirsty/Offspring in danger, so they're ready to fight to the death. Plain grass field, so no homeland terrain advantage. Remember to keep the pro's and con's in mind when deciding.
Who would win the fight?