Gill, who smashed 101 off 58 balls, put on a 147-run stand with Sai Sudarshan, who made 47, to guide table-toppers Gujarat to 188-9 in Ahmedabad.
Mohammed Shami and Mohit Sharma both took four wickets to limit Hyderabad to 154-9 as Gujarat became the first team to secure one of the four play-off spots.
Gujarat, who had a fairytale debut season when they won the title last year, are also assured of a top-two finish in the group phase.
"Very proud of the boys. Two in two. Last year was different, we knew there'd be a lot of challenges this year," skipper Hardik Pandya said.
"Boys have put their hands up in different situations. I think we've rightly earned the chance of making the play-offs."
Hyderabad, the 2016 champions, fell out of the play-off race, making it seven teams fighting for three remaining play-off places.
"Lots of pride still left in the upcoming games," said captain Aiden Markram.
"Maybe we'll give out a few opportunities and guys can finish well but sadly we haven't been good."
Gujarat lost Wriddhiman Saha, for a duck, on the third ball of the match but Gill hit Fazalhaq Farooqi for four straight boundaries to set the pace.
Gill, who jumped to second in the batting charts with 576 runs behind Bangalore skipper Faf du Plessis (631), smashed 13 fours and a six and Sudarshan was also punishing in his 36-ball stay.
Gill, who has scored a ton each in all three international formats, was named man of the match.
Hyderabad hit back with wickets and despite Gill's century in 56 balls, Gujarat managed just 34 runs in the last five overs and lost seven wickets.
The Sunrisers bowlers did well to check Gujarat's total, which looked like going over 200, as seam bowler Bhuvneshwar Kumar returned figures of 5-30 but the efforts were vain.
Hyderabad were never in the chase after they fell to 12-3 with Shami taking two and further slipped to 59-7.
South Africa's Heinrich Klaasen then smashed 64 and put on 68 runs with Kumar, who made 27, but the stand only reduced their margin of defeat.
