What Australia learned last night

A flexible batting order can be crucial

Australia captain Steve Smith has repeatedly stated his desire for Australia's middle order to be fluid and Pakistan proved in Kolkata just how effective a flexible batting order can be.

After Mohammad Shehzad and Mohammad Hafeez had moved the score to 121 with 6.1 overs remaining, skipper Shahid Afridi elevated himself up the order from No.7 to No.4 - and the fireworks began.

Afridi's brilliant 19-ball cameo of 49 all but put the match beyond Bangladesh's reach, while big-hitters Umar Akmal and Imad Wasim were also promoted in the order during the chaotic final overs.

It appears likely that Smith and David Warner will trade places at No.3 and No.4 in Australia's batting order, depending on the situation of the match, while the likes of Glenn Maxwell could see himself as high as first drop should the situation demand it.

Quick Single: Afridi fires Pakistan past Bangladesh

With the likes of Nathan Coulter-Nile, John Hastings and even Adam Zampa capable of clearing the rope, expect Australia's batting order to change on the run throughout the tournament.

Velocity can still be king

With all the talk about how spin will dominate in this tournament, it was refreshing to see the sheer pace of Mohammad Amir proving to be just as effective against Bangladesh in Kolkata.

The speedy left-armer, who continues to impress in his comeback from a spot-fixing ban, ripped through Bangladesh opener Soumya Sarkar with just his third ball, the left-hander castled as he was completely beaten for pace (watch in the video below).

While Amir is quicker than most, it proves that the pace of Australia's quicks Nathan Coulter-Nile, Josh Hazlewood and even Mitchell Marsh can still be effective if they get their lengths right.

And with Australia's final two Group 2 matches to be played in Mohali, which is regarded as one of the faster pitches in India, it's likely the fast men will still have a big impact on the tournament.

When Pakistan are hot, they're unstoppable

With just three wins from their past 10 matches, a skipper under fire and accused of treason, a final XI far from settled and against a team that was on a five-match winning streak against them, not many gave Pakistan a chance against Bangladesh on Wednesday night.

But in little more than hour, Shahid Afridi's men proved the long-held theory about Pakistan cricket - expect the unexpected.

This was the near perfect T20 match from the men in green.

Their top order expertly laid the platform for some big hitting late in the innings - which the middle order produced magnificently - and then, with Bangladesh on the ropes, they struck early and then slowly squeezed the life out of their opponents.

World T20 Today: England clean up after strong Gayle

Which Pakistan will show up for their clash with Australia in Mohali on March 25? Who knows.

Group 2 is wide open

Two matches so far in Group 2 have produced two upset results, blowing the group wide open and putting all sides in contention to qualify for the semi-finals.

While Pakistan's win over Bangladesh was nowhere near as big an upset as New Zealand's thumping of India on the opening night, it was still a surprise result given the form lines of both teams.

Australia will begin their campaign against the Black Caps on Friday and while a win would give them the perfect start, a loss would not be fatal to their chances of finishing in the top two and advancing to the semis.

It seems that all five teams can beat the other on any given day, making for some exciting cricket over the next few weeks.

Is old, is still good

Western Australia and Perth Scorchers coach Justin Langer has long held the theory that Twenty20 is an old man's game and veterans Shahid Afridi and Chris Gayle proved that in spades last night.

Afridi, 36, was a clear man-of-the-match in Pakistan's thumping win over Bangladesh, hammering 49 from just 19 balls after elevating himself to No.4 in the order and then taking two wickets with his leg-spin to move to 95 career T20I wickets.

Gayle, who is six months older than Afridi, also proved a match-winner in powering a 47-ball century against England, the fastest ever in World T20 cricket.

Incredibly, Australia's high turnover of senior players in the past 12 months means just one member of their 15-man squad is older than 30, that being 34-year-old allrounder Shane Watson.

Quick Single: England flattened by Gayle force

While Bangladesh also has a very young squad, Australia's other Group 2 rivals will base their campaigns around players well and truly in the veteran stage of their careers.

Along with Afridi, Pakistan will rely on Mohammad Hafeez and Mohammad Shami (both 35), Shoaib Malik (34) and paceman Mohammad Irfan (33), while New Zealand veterans Grant Elliott (36), Nathan McCullum (35) and Luke Ronchi (34) are all part of their best XI.

Hosts India also have a heavy reliance on experience with four players - MS Dhoni, Ashish Nehra, Yuvraj Singh and Harbhajan Singh - aged 34 and older.

Will Australia's youth triumph over the experience of their rivals? Only time will tell.