Calcutta: Little did Steve Smith know when he departed for just one that things would be so smooth for Rising Pune Supergiant later at the Wankhede on Tuesday.

Ajinkya Rahane (56 off 43 balls), Manoj Tiwary (58 off 48 balls) and former captain Mahendra Singh Dhoni (40 not out off 26 balls) stretched the team total to a competitive 162 for four after Mumbai Indians won the toss and opted to bowl.

Thereafter, young Washington Sundar spun the two-time champions' top-order out and they just couldn't recover from that jolt.

His team having pulled off a comprehensive 20-run victory in Qualifier I to make the IPL X final, captain Smith, no wonder, is proud of his players' efforts.

"It has been really good this year. It's the third time that we have beaten them (Mumbai Indians) this year.

"It was a big day and our big players stood up. We've got the momentum we needed," Smith said at the post-match presentation.

"Manoj and MS Dhoni were magnificent, and Rahane too was very good at the start. Since we went with a batsmen less, we had to be a bit conservative. But 162 was a good total on this wicket, which was on the slower side and as a result, it was difficult to time the ball.

"But truly, Manoj and MS did wonderfully well. We have peaked at the right time, which is important in a tournament like this. I'm really proud of the boys."

Smith was effusive in his praise for Rising Pune bowlers, particularly 17-year-old Sundar. "We bowled back of a length and tried to take the pace off the ball. That has worked for us right throughout the tournament.

"There was dew, but the wicket was still slow. And to speak of Washington, he was really magnificent.

"He bowled a brilliant length and it was great to see him deliver in such a way in the big stage... Really proud of his efforts," Smith elaborated.

"It's really exciting time for us. Hopefully, we can be the better team in the final," the skipper added.

Finishing with figures of 4-0-16-3, Sundar also turned out to be the youngest Man of the Match in the IPL. He owed it to his parents.

"It's very heartening for me to do well against a big team on a big stage in front of a packed crowd. I owe this to my mom and dad," the youngster said.

He might be only 17, but Sundar seems matured enough to understand that trying out too many things at this stage could affect his bowling. "I think keeping things simple works for me and at present, I am not looking to be experimental. Mahi bhai has been supportive in this regard.

"I am just looking to go out there in the middle and back myself," he said.

Sundar is confident Rising Pune can win Sunday's final as well. "I believe we can win the final too and lift the trophy."

On the other hand, Mumbai Indians captain Rohit Sharma minced no words to call this performance as his team's worst so far in the competition. "I think 162 was below par to be very honest.

"Having seen the scores chased down at the Wankhede, I think 162 was below par. But we just didn't bat well. Our worst performance of the season so far.

"We need to build small partnerships when we are chasing. We always knew the wicket will play slow and it was not a flat one where you can play shots on the rise. At the same time, Pune bowlers also really bowled well."

Rohit added: "We need to go back to the basics and try and take the game till the end, which we didn't in this case... We have lost games before too, so it's not the end of the world. We are going to go back and see what we can do in Bangalore (in Qualifier II)."

Rohit also pointed out that shot selection is one area where his team needs to work on. The shots that some of the top and middle-order batsmen played were really poor.

"Shot selection is very important. You need to understand the situation and the conditions, and respect them.

"You've got to pick the gaps and take it to the end. We couldn't do that today and you can see the result.

"So, we need to brush up and make sure we do it fast," the Mumbai Indians skipper emphasised.

Lendl Simmons and Parthiv Patel had got Mumbai Indians off to a steady start in their reply, knocking off 35 runs in the fifth over.

But soon after, Mumbai Indians lost half their side adding only 40 more. And they could never come back from that position.