Why did Sam Curran open the batting?

No team had scored as slowly as the Super Kings in the powerplay this season ahead of this game, and they decided it was time to change things: after 68 runs off 31 balls in the middle order, Curran was promoted to open the batting for only the second time in his T20 career.

The move looked to have backfired after three overs, with Curran struggling to time the ball and batting uncharacteristically defensively on 10 off 15, as Faf du Plessis nicked off for a first-ball duck. But Curran heaved two fours and then two sixes in the fourth over off Khaleel Ahmed, and had done his job by the time he was bowled by Sandeep Sharma in the fifth over for 31 off 21.

Why did Super Kings pick Chawla for Jagadeesan?

The Chennai Super Kings picked only five frontline bowling options in their side for the tournament opener against the Mumbai Indians. But they started the second half of the season with seven, as Piyush Chawla came in for N Jagadeesan for Tuesday night's game against the Sunrisers Hyderabad.

That allowed MS Dhoni to use specialists in certain phases and target individual batsmen with specific bowlers: new-ball specialists Deepak Chahar and Sam Curran split the first seven overs between them, while Dwayne Bravo was held back until the 14th over. Chawla bowled only six balls, being used in the 16th over to take the pace off against a set Kane Williamson and conceded just eight runs.

Why did Karn Sharma bowl the 18th over?

Given their plethora of bowling options and with two death-over specialists in Bravo and Shardul Thakur, it was a surprise to see Dhoni turn to legspin in the 18th over. Dhoni is not a captain who relies on analytics, and may not have known that Williamson's strike rate against legspin in the IPL since 2018 was 112.09 coming into this match. He seemed to have clearly decided from his reading of the game that Williamson was desperate for pace on the ball.

Dhoni's ploy worked initially: Williamson lofted a one-bounce four over square leg before holing out to long-on, seemingly ending the Sunrisers' chances. When Rashid Khan and Shahbaz Nadeem took 15 from the next four balls between them, it looked as though it might have backfired, but Thakur's excellent 19th over made the game safe for the Super Kings.

Did umpire Paul Reiffel change his mind in the 19th over?

play
2:21

Did Paul Reiffel change his mind after seeing Dhoni?

Ian Bishop and Deep Dasgupta on a key moment in the chase

With 25 required from 11 balls, Thakur sprayed a ball just outside the tramlines that Khan couldn't reach, and umpire Reiffel rightly gave a wide. The next ball was almost a carbon copy, but Reiffel stopped halfway through calling another wide as Dhoni and Thakur protested.

Replays showed that the ball had clearly jagged past the wide line again, and David Warner was visibly frustrated with the call in the Sunrisers' dugout. It might not have made a difference given the collapse that followed, but it left the required rate at 14.40 runs per over rather than 12.50.

Why did Shane Watson score so slowly?

Curran's promotion meant that Watson batted at No. 3 - the first time in 40 innings that he had not opened while playing for the Super Kings. Notoriously a slow-starter, Watson eked out only four runs from his first 11 balls before flicking a trademark pick-up over square leg to hit T Natarajan for six.

There were moments in the middle overs against Nadeem - whom he has struggled against in the past - and Khan when he looked as though he was about to put his foot down, like he had against the Sunrisers in the 2018 final. But when Watson eventually holed out to long-off, he had managed only 42 runs while chewing up nearly a third of the Super Kings' overs by himself.

It is surely too soon to write Watson off - he has proved in the past that he can recover from slow starts in a tournament, as well as in an innings - but with his strike rate this season down at 122.33, he will know that he has to start firing soon.

Is Khan losing his spark?

After eight wickets with an economy rate of 4.83 in his first six games of the season, Khan has returned combined figures of 2 for 55 in eight overs across his last two appearances. Those numbers are still good by normal standards, but there have been signs that teams are increasingly willing to take him on.

In particular, it has been instructive to see how teams have approached the fourth over of his spell. In the first six games, teams looked to play him out, taking a combined 28 runs for three wickets across his six final overs. But needing 36 off 18 balls when he returned for his last over in the Sunrisers' previous game against the Rajasthan Royals, they had no choice but to attack; and Rahul Tewatia did just that by hitting him for three fours. On Tuesday, Watson and Ambati Rayudu hit him for a six each in his fourth over.

It will become apparent over the next two weeks whether those two assaults were the result of circumstances or a sign that teams are now willing to attack him.

Has Dhoni decided to follow the trend of batting first?

After winning 22 tosses out of 27 in a remarkable streak dating back to the 2018 season, the Super Kings had lost their last four tosses in a row coming into this game. They had chased in every game in the first half of the group stage, losing five and winning two.

On Tuesday, Dhoni won the toss, batted first and continued the trend in this tournament of teams successfully defending scores. Discounting games that went to Super Overs, the team batting first has won 20 out of 27 matches this season. With pitches slowing down and thus becoming increasingly similar to their Chepauk home ground, there are reasons for the Super Kings to believe they can extend their record of making the playoffs every season.