Sunrisers Hyderabad beat Rajasthan Royals by 36 runs on Friday to set up an IPL final against Kolkata Knight Riders, as spinner Shahbaz Ahmed starred with three wickets.

Heinrich Klaasen smashed 50 off 34 balls to help Sunrisers post 175-9 and their bowlers combined to restrict Rajasthan to 139-7 as they reached their third IPL final, to be played in Chennai on Sunday.

Ahmed came in as an impact substitute in Hyderabad's batting innings to score 18 runs and then returned figures of 3-23 with his left-arm spin to flatten the opposition chase.

Kolkata, who thrashed Hyderabad in the first play-off game to reach their fourth final, will meet Pat Cummins' side again in the decider.

Cummins, who cost Hyderabad $2.5 million at the auction, remains on the cusp of another title after he led Australia to the Test championship trophy and then to the ODI World Cup in India last year.

"You've seen that in the way we played," Cummins said on his team's turnaround from last year when they ended bottom of the 10-team table. "The finals was the goal and we've made it."

Ahmed was named player of the match and Cummins said it was coach Daniel Vettori's call to have the all-rounder come in as impact sub.

It took time to fill the 36,000-capacity M.A. Chidambaram Stadium, with local fans still missing the presence of home team Chennai Super Kings.

Chennai veteran M.S. Dhoni remains a hero in the south Indian city and many fans wore his number 7 jersey during the third play-off contest.

The IPL was in the grip of a heatwave in the last two play-off matches in Ahmedabad, where temperatures soared to over 44 degrees Celsius (111 degrees Fahrenheit), but Chennai remained much cooler at 32 degrees.

Rajasthan faltered in their chase despite Yashasvi Jaiswal's quickfire 42 before the opener fell to Ahmed and skipper Sanju Samson soon departed for 10.

- 'Great talent' -

Ahmed strick twice in one over, including the in-form Riyan Parag for six, and despite Dhruv Jurel's late unbeaten 56, inaugural champions Rajasthan fell well short.

"We've had some brilliant games, we've had a great project as a franchise," said Samson. "We've produced some great talent for the country. Parag, Jurel, exciting not only for RR but for India team too."

Hyderabad's Abhishek Sharma scored 12 but returned with his part-time spin to take two wickets including the big-hitting Shimron Hetmyer, bowled for four.

Earlier Sunrisers, who had racked up record IPL totals of 277 and 287 this season, lacked firepower in their batting until Klaasen boosted the score with his fourth fifty of the season.

Rajasthan's Trent Boult made early inroads when he got Abhishek in the first over and struck twice in the fifth to send back Rahul Tripathi, for 37, and Aiden Markram, for one.

Fast bowler Avesh Khan took two wickets in two balls, prompting Hyderabad, who won the IPL in 2016 under Australia's David Warner, to bring in Ahmed.

South Africa's Klaasen stood firm to reach his fifty from 33 balls and put on a key seventh-wicket stand of 43 with Ahmed in a total which proved enough.