In the last week of March this year, Chennai Super Kings lost the toss in two successive matches, bringing a brief break to an incredible run of luck. Either side of those two lost tosses, spanning IPL seasons, are winning streaks of eight and nine with the coin.** They have lost just six of this run of 19 matches overall. At the bottom of the IPL 2019 points table, Royal Challengers Bangalore have won just three of their 13 tosses this season.

Super Kings have won 10 tosses this season; they have three to five matches remaining, which means they have a good shot at going past the record for one season: 12.

You can't take credit away from Super Kings for knowing what to do after winning those tosses and doing it well, but you also know the toss is more important here than in ODIs from the clear formula developing: chase, rare circumstances aside - which is the exact opposite of Tests. Champions in eight of the 11 previous editions of the IPL have also been sides that had won the most tosses in that season.

Super Kings have played those 19 matches mentioned earlier over eight venues, but on the 17 occasions that they have had the right to choose what they want to do first, they have batted only on three occasions. Yet, when the IPL started, it followed the traditional wisdom of cricket: runs on board, scoreboard pressure when chasing etc. It was only 2014 onwards that sides began to prefer chasing consistently.

Percentage of times teams chose to field first ESPNcricinfo Ltd

As you would expect, teams were wary of dew at the start of IPL, which explains a higher preference for chasing in 8pm games in the early years. Yet there was this year - 2013 - when they chased only in 39% of the night games. Then in 2014 the penny dropped.

Percentage of times teams chose to field first in the 8pm game ESPNcricinfo Ltd

It was still felt that 4pm games gave you more incentive batting first.

Percentage of times teams chose to field first in the 4pm games ESPNcricinfo Ltd

There is no particular event that marks a turning point in the attitude of the sides. It was more a gradual realisation that 40 overs is too short a time for the conditions to bring their whole gamut into play. Teams began to understand that the availability of disproportionate wicket resources over 20 overs meant you never knew what the chasing side could do with its resources. Often teams batting first lost only two or three wickets in their innings, but that target would be chased down. They just didn't know how hard to go when batting first, so they began to chase.

There was a theory that sides preferred to begin batting first as the season wore on and pitches grew tired, and that was the only consideration holding chase numbers back in the earlier years. However, that deviation is not big, especially in recent seasons. In 2014, you will see sides chased more as the season went on, but that is because it began in the UAE before coming to chase-friendly Indian conditions.

ESPNcricinfo recently did a study on how much ODIs have changed over the last 20 years. We looked to see if any one decision at the toss held an advantage over time. The advantage criss-crossed over the years before settling beautifully to be even in day-night games in the period leading up to the upcoming World Cup. The difference in day games was minimal. In T20 cricket, though, the balance is tilted towards the chasing side and has stopped yo-yo-ing. That makes the toss important, although not as important as in Test cricket between evenly matched sides.

How successful are teams that chase? ESPNcricinfo Ltd

Filter the numbers mentioned above by grounds and years, and it tells you more. Grounds such as Rajkot, Pune, Kanpur and Indore, which hosted matches only during this chase revolution, have no semblance of balance. Gujarat Lions and Rising Pune Supergiant(s) have great win-loss ratios when chasing. Supergiant(s), who were at their heart a Super Kings spin-off, reflected the same kind of success when chasing.

It was in 2016 that this whole shift seemingly became irrevocable. This is when the real difference can be sides who manage to win when inserted. Super Kings again have the best win-loss ratio here, but they have been away for two of these years and they have hardly lost tosses since coming back. Not surprisingly, Mumbai Indians and Sunrisers Hyderabad have done well on that count.

Who wins the most after being put in to bat? ESPNcricinfo Ltd

Is it important, then, to keep challenging yourself on and off by batting first so that you stay in touch with what is required when you're forced to do so? Not many teams feel that way. They bat first only when they are assured the pitch will deteriorate and that there will be no dew in the second innings. Still there are sides that do it more than others. Since the start of 2016, teams have chosen to bat once every six games. Delhi Capitals lead the way by doing so once every four games, which might tell you a bit about the Feroz Shah Kotla pitch. Super Kings, on the other hand, do so once in seven games. Gujarat Lions did it once in 15 times of asking.

Top-four toss winners every IPL season ESPNcricinfo Ltd

**All stats are correct as of April 30, 2019