Complex sentence: In the 2015/16 season he played an integral part in Northampton's League 2 title winning season, where they narrowly missed out on also securing the award for "best team in League 2" to Oxford United.
Split into simpler sentences: In the 2015/16 season he played an integral part in Northampton's League 2 title winning season. That season Northampton narrowly missed out on also securing the award for "best team in League 2", which was won by Oxford United.