St Helens claimed the League Leader's Shield after Castleford Tigers were defeated by Catalans Dragons in Super League on Saturday.
Saints' position atop the standings after 27 rounds of the regular season was confirmed when Castleford, the only team who could mathematically usurp them, slumped to a 28-6 defeat in Perpignan.
That result means Castleford finish fourth, while Saints stumbled their way to claiming the Leader's Shield after narrowly losing 17-16 to Huddersfield Giants on Friday.
It marks the first time since 2008 that the Merseyside club have finished top and they will now meet Castleford in their qualifying play-off match at Langtree Park next Friday.
Wigan Warriors entertain Huddersfield Giants, after the duo finished second and third respectively in the final standings.
In the elimination play-offs Leeds Rhinos, the only team in history to the win the Super League title from fifth, start their attempt to go one better by triumphing from sixth against the Dragons at Headingley next Saturday.
The other elimination play-off sees Warrington Wolves tackle Widnes Vikings.