The 19th-over specialist, 50 runs off four overs, and other trends in the IPL

T20 cricket has come a long way from the early days. From being seen as just a hit-and-giggle version of the game to being regarded as one of its most inventive formats. The urgency to make things happen within 20 overs has necessitated a number of innovations in the game both on the field and off it, and the T20 game these days is played quite differently from how it was played a decade ago.

While players themselves have invented new skills on the field, technological improvement in coverage of the sport has enabled teams to take a significant part of the cerebral battle off the field. The availability of in-depth data on players has enabled teams to plan and strategise around the strengths and weaknesses of the opposition. Even at a wider level, T20 cricket has evolved in adopting playing styles and practices that are more efficient for the game.

As one of the premier leagues of the format, the IPL has been at the forefront of the evolution of T20 cricket. We look here at a few of the more recent strategies and trends that have emerged in the IPL.

The 19th over specialist
The 19th over is increasingly proving to be the make-or-break over in run chases in T20s. And the responsibility of bowling the all-important penultimate over in these situations is falling on an increasingly exclusive group of bowlers. Over the last three seasons of the IPL, there have been 52 instances when chasing teams have had to get between ten and 24 runs with at least three wickets in hand at the end of the 18th over. Both teams in each case could be considered to have a realistic chance of a win from these situations.

Jasprit Bumrah leads the pack of bowlers who are most often bowling the 19th over at this stage of the match. In the last three seasons of the IPL, Bumrah has bowled seven times in these situations, followed by Andrew Tye, who was tried four times. They are among a group of seven bowlers who have bowled the 19th over at least three times, and have been clearly earmarked to snuff out chases before the final over. This group accounted for 50% (26 overs) of the 19th overs bowled in such chases.

In the three seasons before 2017, teams went to only four bowlers more than twice each in such situations, and these bowlers accounted for only 13 of the 47 instances (27.6%).

In comparison, the first three seasons of the IPL saw no such clear strategy. Incidentally, there were exactly 52 instances again when both teams had realistic chances of a win (as defined above) in seasons 2008 to 2010. Only two bowlers - Ishant Sharma and Lasith Malinga - bowled the 19th over three times apiece in such chases. Including them, the seven bowlers who bowled the 19th over more than once accounted for just 16 out of the 52 chases.

50 from the death? Not over yet
While Andre Russell is an extreme example - he helped Kolkata Knight Riders get 60 runs from the last four overs in three chases in the last IPL - of what's achievable nowadays in T20 cricket, the realms of possibility in the death overs are clearly expanding. The last couple of seasons have shown that teams are more likely to chase down 50 in the last four overs than before.

In the first five seasons of the IPL, out of the 116 instances when teams were 50 runs or more short of the target at the end of the 16th over, they managed to get 45 or more on 23 occasions, and they ended up winning 13 out of these 116 chases. However, in the last couple of seasons, teams have got 45-plus runs in 18 out of 39 such chases and won seven of them. That's a jump from 19.8% to 46.2% in terms of the number of times chasing teams have managed to score 45 or more, and a 60% jump in wins in such circumstances. If your team is defending 50 runs or thereabouts from the last four overs, well, don't relax just yet.

Dynamic bowling plans
Captains and teams these days are required to think on their feet and have a few plans up their sleeves to keep batsmen guessing. Unless a bowler is completely on top, captains don't usually bowl him for more than two overs at a stretch. Bowlers are rotated frequently, especially in the middle overs, depending on the batsmen at the crease and the match situation.

Over the years there has been an increase in the number of times bowlers are brought on to bowl just the one over. From 11.6 one-over spells per match in the inaugural season of the league, the average number of such spells has increased to 16.3 per match in 2019. In 2008 only 30.5% of overs were by bowlers who were called on by the captain for just one over. This number increased by nearly 37%, to 41.8%, in 2019.

In the first IPL season, as many as 31.1% of the balls bowled were in spells of three or more overs. This percentage has come down to 23.7% in 2019 (it was just 18.4% in 2017, and 19.1% in 2018).

No place for anchors
Manish Pandey, Ajinkya Rahane and Shikhar Dhawan are among the slowest batsmen who bat at the top of the order in the IPL (their strike rates are among the lowest for batsmen with 100 or more innings in the IPL). Often as a natural consequence, or sometimes by design, teams used to employ them as anchors in the IPL. These batsmen would hold one end up by taking few risks, while others batted around them and took on the onus of scoring quickly.

Until the 2016 IPL season, Pandey, Rahane and Dhawan had a combined total of 41 innings in which they faced 45 or more balls (a top-order batsman usually plays those many balls by the time the death overs arrive). They managed to score at a rate of 150-plus in only seven of these 41 innings. In contrast, since 2017, eight of the 16 innings of 45-plus balls between them have come at a rate of 150 or more. Clearly, these batsmen are looking to score quickly even as they bat through the innings.

This is a manifestation of the change in how teams perhaps look at the role of an anchor. Over the years it has become clear that teams are rarely in danger of being bowled out inside 20 overs. Teams have realised that it is a wasteful luxury to have a batsman play the conventional role of an anchor while batsmen capable of a more aggressive approach run out of deliveries to face. Top-order batsmen, who generally play through a team's innings, are expected these days to accelerate their scoring as the overs tick along. This is especially true with teams batting first, who are not sure about what a good total is.

Overall numbers from the IPL underline this change. Since 2017 there have been 64 innings where batsmen have faced 45 or more balls in the first innings (how quickly or slowly a batsman scores in a chase is dependent on the target and therefore not considered here). In 37 of these innings (57.8%), batsmen have managed to finish with a strike rate of 150-plus. In comparison, in the previous three seasons, from 2014 to 2016, batsmen scored at a 150-plus strike rate in 28 out of 77 innings (36.4%). This is an increase of nearly 60% in innings where batsmen playing through a team's innings have stuck at 150-plus. The median strike rate of these 45-plus ball innings has gone up from 137 to 158 - an increase of 15%. This increase in strike rates is significantly higher than the 4% rise in general scoring rates of batsmen in the top five in the IPL between the two periods.

The role of an anchor in the conventional cricketing sense is arguably defunct in T20s.