They started the year as favourites for the NRL premiership, but Wests Tigers will almost certainly start their Mad Monday celebrations next week after going down 44-20 to the Sydney Roosters at Allianz Stadium.

Requiring a win to move above Brisbane into eighth spot, Tim  Sheens' side now need to topple second-placed Melbourne at  Leichhardt on Saturday and hope lowly Penrith beat the Broncos at Suncorp Stadium 24 hours earlier to have any hope of playing in the  finals.

A hat-trick from giant winger Daniel Tupou, in only his second NRL game, laid the foundations for the win as Brian Smith's side marked Anthony Minichiello's 250th game in style by running in eight tries.

The Tigers, who were without skipper Robbie Farah due to a broken hand, were never at the races in the first half as the  Roosters opened up a 26-0 lead by the break - their highest-scoring opening period since round 18 in 2008.

Frank-Paul Nuuausala opened the floodgates in the 13th minute before Tupou grabbed his first, hauling in a Braith Anasta kick to  the corner and brilliantly putting the ball down.

Tim Moltzen then booted the kick-off out on the full and from the resulting penalty, Shaun Kenny-Dowall scored in the right  corner to leave the Tigers shellshocked.

Young centre Tautau Moga and Tupou went over before the interval  to stretch the advantage further for the hosts, with Anasta, playing his final home game before joining the Tigers next year, kicking three goals.

The second half started in a similar fashion with Mitchell Pearce finishing off a move that had a suspicion of obstruction  about it after he ran behind decoy runner Minichiello, to score and  end the game as a contest.

Stand-in Tigers skipper Benji Marshall did his best to try and inspire his side, firing a brilliant cut-out pass to Marika  Koroibete for the visitors' first try of game and Blake Ayshford scored his fourth of the season shortly after.

ut there was to be no second-half capitulation from the Roosters with Tupou grabbing his third after Junior Moors dropped the ball under his own posts from the kick-off.

Minichiello got in on the scoring act 13 minutes from time, much  to the delight of the crowd after some unselfish play from Pearce, who crossed the line but flicked a pass so the veteran fullback could touch the ball down.

The Tigers finished with some pride, scoring two late tries as Chris Heighington marked his 200th game with a four-pointer before Ben Murdoch-Masila crossed.

Marshall was put on report for a high shot on Jared Waerea-Hargreaves.

- AAP