His 129.9 passer rating is highest of any player since 1966 in first two career starts .
Titans QB Marcus Mariota is first player in NFL history with six TD passes in first two career games .
Marcus Mariota 's 129.9 passer rating is highest of any player since 1966 in first two career starts .
Titans QB Marcus Mariota is first player in NFL history with six TD passes in first two career games .