Second-rower Angus Crichton scored his second career hat-trick as the Roosters went to 36 points on the ladder with their win at Robina and ousted Penrith from second based on a superior for-and-against.
The Tricolours can wrap up a top two finish if they beat Canberra and South Sydney in their remaining matches.
The Roosters lost Waerea-Hargreaves to the sin-bin in the 12th minute when the firebrand was put on report for an incident in the lead-up to a try to Titans winger Alofiana Khan-Pereira.
Angus Crichton scored a hat-trick as the Roosters ran riot at Robina. (Dave Hunt/AAP PHOTOS)
Waerea-Hargreaves, in his first game back from a four-match suspension, was pinged on review by The Bunker for forceful contact to the head of Titans hooker Sam Verrills .
Due to his prior offences, a grade two charge by the match review committee would lead to a three-match ban.
If the Roosters don't make the top four and were to lose their opening final, unlikely though that is, that would be the end of Waerea-Hargreaves' NRL career. The three-time premiership winner will join England's Hull Kingston Rovers next season.
The Roosters lost centre Joseph-Aukuso Suaalii to a shoulder injury in the first half but early reports suggested it was less serious than first feared.
Roosters hooker Brandon Smith was a late withdrawal with injury and was replaced by Zach Dockar-Clay, who charged through the middle early before forward Angus Crichton scored the opening try in the fourth minute.
Sitili Tupouniua scored the last of his side's nine tries as the Roosters moved to second spot. (Dave Hunt/AAP PHOTOS)
The Titans hit back with Khan-Pereira scoring the first of his three tries of the afternoon.
Roosters No.6 Luke Keary put a deft lob in for winger Dominic Young to score in a sublime piece of skill by the veteran.
Khan-Pereira then beat opposite number Dom Young twice, Joey Manu and James Tedesco in a 90m run to the line in which he didn't run at full pace once in a remarkable display of athleticism.
Roosters half Sam Walker went over and winger Daniel Tupou scored a double in a try blitz before halftime for the visitors to take a 26-10 lead.
When skipper Tedesco scored the first try after the break the result was sealed. The Roosters then ran riot as only they can.
Titans second-rower David Fifita and his counterpart Crichton played out an engrossing battle within the battle - understandable considering Fifita backflipped on joining the Tricolours earlier in the season.
