Former NRL star Willie Tonga was knocked out just 12 seconds into his Super League debut on Friday as his Catalans Dragons side lost 18-7 to champions St Helens.

Tonga was injured in the very first tackle of the match at Langtree Park as he attempted to bring down Saints prop Alex Walmsley.

The game was held up for eight minutes before Tonga was carried off on a stretcher and was later reported to be "fine".

Atelea Vea marked his St Helens debut with the game's first try and teenager Andre Savelio scored his maiden try for the club.

Fellow NRL defector Todd Carney missed out on his Catalans Dragons debut with a calf injury.

AFP