Bottom of the table heading into their final group game, Chennai posted a mammoth 230-5 after electing to bat at the Narendra Modi Stadium. Conway smashed 52 off 35, while Brevis lit up the back end with a blistering 57 off just 23 balls, combining with Ravindra Jadeja (21 not out off 11 balls) to hammer home a dominant finish.
The bowlers backed up the batters in style, dismissing Gujarat for just 147 in 18.3 overs, with Anshul Kamboj and Noor Ahmad taking three wickets apiece to cap a rare complete performance from the five-time champions this season.
CSK finish the season with just four wins in 14 games - far from their usual standard - and with speculation swirling around the future of MS Dhoni, who stepped in as captain mid-season after Ruturaj Gaikwad's injury.
Speaking at the toss, Dhoni, 43, was tight-lipped about whether this was his final IPL appearance.
"Every year's a new challenge, especially at this stage of your career. You've got to respect the body," Dhoni said. "I thank God that it didn't trouble me when I was playing for India."
For Gujarat, the loss comes as a setback heading into the playoffs. Already qualified, they now finish the group stage with 18 points but lose momentum - and face the risk of missing a top-two finish, which would have guaranteed a second shot at the final.
The match also spotlighted Gujarat skipper Shubman Gill, playing just a day after being named India's new Test captain. He managed only 13 off nine balls and was the first to fall in a chase that never got going. England's Jos Buttler (13) and West Indies' Sherfane Rutherford (0) fell cheaply as GT crumbled to 30-3.
Sai Sudharsan top-scored with 41, but the rest of the line-up faltered as CSK bowlers ran riot.
Earlier, 17-year-old Ayush Mhatre (34 off 17) and Conway gave Chennai a flying start. After their dismissals, Urvil Patel, Shivam Dube, and Brevis continued the onslaught. Brevis and Jadeja added 74 runs from just 39 balls, sealing Gujarat's fate well before the second innings ended.
As the playoff race heats up, Gujarat, Punjab (17 points), Bengaluru (17), and Mumbai (16) remain locked in a tight battle for the top two spots, with each side having one match remaining. The final is set for June 3.