There was no fitting conclusion to the former Kiwis skipper's 259-game first grade career as the Warriors unleashed a second-half blitz to surge to a 26-12 victory at Parramatta Stadium.
Their reward is a trip to the Gold Coast, where they play the fourth placed Titans on Friday night -- a club they have lost to in both meetings this season.
The Warriors survived the justified sinbinning of five-eighth James Maloney and a caning in the penalty count to finish strongly against an Eels side inspired by Cayless's swansong.
Ironically it was a rare Warriors penalty in the second half that swung momentum the visitors way.
Backchat advanced the Warriors into attacking position and the call to reject a handy two points was justified when interchange prop Jess Royal touched down under the posts after taking a smart Brett Seymour flick pass.
A converted try by Kevin Locke then made the game safe at 20-6 -- a sad outcome for Cayless whose missed tackle on Aaron Heremaia set the Warriors' fourth try in motion.
Manu Vatuvei then equalled the Warriors' all time tryscoring record, joining legendary halfback Stacey Jones on 77.
When he muscled past marker and 2011 Warriors recruit Krisnan Inu with 12 minutes to play, the damaging wing also matched the 19 tries Sean Hoppe recorded in a regular season.
At least Cayless had some cause for celebration at the close of his 14-year career when he scored a popular consolation try with five minutes remaining -- his first since mid-2007.
Fittingly Cayless made the game's first hit-up and the Warriors worked hard on defence early, combating three consecutive sets before Inu lost control of a grubber over the line.
The former Kiwis wing made amends soon after when he batted down a pass for a try-bound Vatuvei.
The Warriors then forced four successive goal line dropouts and the pressure eventually told on their next possession in the 16th minute when a Brett Seymour grubber sat up perfectly for Jerome Ropati who grounded the ball centimetres inside the touchline despite the attention of Jarryd Hayne.
The arm wrestle continued unabated, both sides absorbing huge defensive workloads before a raking punt from a penalty set up a controversial try to Timana Tahu.
The former dual international retrieved the ball 10m out from the Warriors line and was allowed to advance another 5m, catching the defenders unaware as he tapped to himself and crashed over to put the Eels on the board on the half hour.
Warriors captain Simon Mannering remonstrated in vain with referee Matt Cecchin, arguing the referees were not in the correct position when Tahu made his move.
But the Warriors were in a better frame of mind three minutes later when Brent Tate outlasted Nathan Hindmarsh in a foot race to the right hand corner after Locke grabbed a chip ahead by Hayne.
Parramatta claimed the ball was illegally shielded by Brett Seymour before Locke grasped it and scorched clear over halfway before linking with Tate.
Video referee Russell Smith confirmed the score, his first contentious decision of a frantic end to the opening spell.
Smith infuriated the Eels with time up on the clock when he declined to award the home side a penalty try after Luke Burt was cynically tackled without the ball by Maloney 12m from the line.
Fortunately for the Warriors Mannering was tracking back in cover and may have reached the ball even if Burt had not been impeded.
However, Maloney was marched for the offence and the Warriors clung to an 8-6 advantage after Inu missed the resulting penalty.
Vatuvei, who played despite being troubled by a knee injury, caused a minor scare in the 27th minute when he buckled backwards when tackled by interchange prop Tim Mannah.
He needed treatment on his left leg but was able to continue and made a couple of trademark busts -- and handily deflected a penalty in field when the Eels tried in vain to benefit from their numerical advantage.
