MUMBAI: Opening batsman Faf du Plessis smashed an unbeaten half century and anchored Chennai Super Kings to its seventh Indian Premier League final with a thrilling two-wicket victory over Sunrisers Hyderabad in the Qualifier 1 on Tuesday.

Du Plessis' 67 off 42 balls took Chennai to 140-8 as the South African brought up the victory with a straight six off Bhuneshwar Kumar's first ball of the last over.

Hyderabad had the match in its grip until the 17th over with Chennai needing 43 runs and three wickets in hand.

But du Plessis caressed three fours and a six as seamer Carlos Brathwaite conceded 20 runs in the 18th over.

No. 10 batsman Shardul Thakur (15 not out) then managed to hit three boundaries off Sidharth Kaul's 19th over which went for 17 runs and put the game beyond Hyderabad's reach.

"Faf's innings is where experience counts," Chennai captain Mahendra Singh Dhoni said.

"It's not easy to not play a lot of games, but I always say you need to train your mind as well. That's where the experience comes in. You visualize what your role is, how you can contribute and Faf has been brilliant."

Hyderabad gets another chance to have a shot at the title on Sunday against Chennai as it meets the winner of Eliminator 1 between Kolkata Knight Riders and Rajasthan Royals on Friday.

Hyderabad lived up to its reputation of defending low totals after captain Mahendra Singh Dhoni won the toss and restricted his opponents to 139-8.

Kumar had Shane Watson dismissed for zero with an impeccable away swinger in the first over and Kaul knocked back the stumps of in form Suresh Raina (22) and Ambati Rayudu (0).

Afghanistan legspinner Rashid Khan (2-11) brilliantly mixed up his googlies and sharp leg breaks in his four overs as he dismissed Dhoni (9) and Dwayne Bravo (7).

Seamer Sandeep Sharma (2-30) had the wickets of Ravindra Jadeja and Deepak Chahar in successive overs of his return spell and reduced Chennai to 92-7 in 15 overs before du Plessis kept his cool and guided Chennai to victory.

Earlier, Hyderabad top order stuttered against seamers in the batting powerplay as Shikhar Dhawan dragged Chahar back onto his stumps off the first ball.

Captain Kane Williamson (24) also departed as he gloved Thakur's short pitched delivery to Dhoni behind the wickets in the fifth over.

Bravo then chipped in with 2-25 that included a smart return tumbling catch to dismiss Yusuf Pathan before Brathwaite smashed 43 off 29 balls and Hyderabad scored 51 runs off the last five overs.

"The game did swing our way, and bowlers were outstanding, but we didn't quite execute it like in the past," Williamson said. "Hopefully we can cross the line in Kolkata and come back here (for the final). Faf played a beautiful knock, and credit to the way they scrapped it."