Morris hurt his groin in the warm-up and Ikuvalu made the most of his first game since round two to equal Brian Allsop's haul against Parramatta at Sydney Sports Ground 65 years ago.
South Sydney flyer Alex Johnston had been most recent NRL player to bag a quintet with his 2017 effort. Coming into the clash on Thursday, Ikuvalu had scored four tries in 15 NRL appearances.
You couldn't tell from the final scoreline but the Cowboys had the upper hand early as the Roosters completed just 64 per cent of their sets in the opening stanza at Queensland Country Bank Stadium.
But they exploded with five tries in 20 minutes after the break to cruise to victory, the right edge attack giving their opponents nightmares.
Tricolours five-eighth Luke Keary grabbed a double while fullback James Tedesco ran riot, threatening with almost every touch to record 236 metres and two try assists.
Morris joined captain Boyd Cordner (rested), winger Daniel Tupou (syndesmosis), Isaac Liu (broken rib), Victor Radley (ACL) and Sam Verrills (ACL) in a bursting Chooks casualty ward.
Hooker Jake Friend was replaced by Lachlan Lam in the 24th minute after a head knock.
North Queensland didn't emerge unscathed either, with Valentine Holmes unable to play the second half due to his ongoing ankle complaint.
Holmes, who swapped from fullback to wing, admitted to Fox League pre-match that he wasn't at full fitness and it showed when he began hobbling.
North Queensland beat the premiers without Cordner in round 17 last season and they looked intent on creating another boilover with plenty of intensity to start.
They eventually broke through in the 23rd minute via robust hooker Reece Robson. The former Dragon took advantage of a quick Jason Taumalolo play-the-ball, deceiving Nat Butcher at second marker with a dummy and carrying him and Tedesco to the line.
A penalty for a high tackle against prop Jared Waerea-Hargreaves allowed Kyle Feldt to line up a close-range penalty goal which would have made it 8-0 but he sprayed it into the post. The Steeden ricocheted to the Cowboys but they couldn't turn it into a try.
Tedesco produced some magic to get his team on the board in the 32nd minute, silkily shovelling on a Kyle Flanagan pass to send Ikuvalu over.
Siosiua Taukeiaho ensured the Chooks led at the break. The prop shaped to pass and burst past Robson, then flicked to Sitili Tupouniua who reaped the rewards for pushing up in support.
Whatever Trent Robinson told his troops at half-time worked instantly as Ikuvalu scored back-to-back tries to stun North Queensland. Ikuvalu first produced a sensational airborne finish and his next play was just as impressive, staying inside the touchline by millimetres.
Their right-edge attack humming, the Roosters notched their third try in five sets when Tedesco broke into the clear from a Flanagan inside ball and linked with Keary.
Moments later Keary was over again after Tedesco put prop Lindsay Collins in space and he found the playmaker racing up alongside him.
A Flanagan long ball positioned Ikuvalu one-on-one with Ben Hampton and he proved too strong to grab his fourth in the 61st minute. Keary kicked across field for the man of the moment to soar high for his fifth.
Cowboys back-rower Coen Hess and Robson crashed over for consolation tries at the death but they couldn't take the gloss away from Ikuvalu's incredible night. - NRL