Speaking to ESPNcricinfo after Pakistan's Champions Trophy victory last year, bowling coach Azhar Mahmood uttered a memorable line: "batsmen win you games, bowlers win you tournaments."

It's a theory a number of coaches buy into, and one the numbers support as well.

Perth Scorchers' strategy of investing heavily in their bowling combination, under coach Justin Langer, has led them to three Big Bash League titles and two runner-up finishes. All this in only seven years of the tournament. Year on year, Scorchers have rarely outhit their oppositions, but have more often than not outbowled them.

Another T20 team in bright orange, Sunrisers Hyderabad, follow the same principles. They won the 2016 IPL with the worst middle order in the tournament but easily the best bowling attack, and they have stuck to that template since.

Take this year's player auction, where their coach Tom Moody had the opportunity to build a team from scratch. Retaining Bhuvneshwar Kumar, their spearhead for the past two seasons, was a no-brainer, as was buying back Rashid Khan, the world's best T20 bowler. But they kept stockpiling even more bowling options. They bulked up their overseas quota with the tall and pacy Billy Stanlake and allrounders Chris Jordan, Carlos Brathwaite, Shakib Al Hasan and Mohammad Nabi.

And they kept picking up Indian fast bowlers, one after another, while other teams passed up the opportunity. Sunrisers bid aggressively for Basil Thampi, Siddarth Kaul, Sandeep Sharma, T Natarajan and Khaleel Ahmed. It was clear they were backing their bowlers to win them games this season, and boy, have they delivered.

In the season's first three games, Sunrisers restricted their oppositions to totals of under 150 and chased them all down. That was expected to be their blueprint, and Rashid, Bhuvneshwar, Stanlake and Shakib all played their part in the wins. Two losses followed in batting-friendly conditions, and then came the acid test - injuries to Bhuvneshwar and Stanlake.

The blow would have crippled any other team. Imagine Mumbai Indians losing Jasprit Bumrah and Mustafizur Rahman. But this was exactly what Sunrisers had prepared for. In came Sandeep, with the ability to swing the ball both ways like Bhuvneshwar, and Thampi, not as tall as Stanlake but almost as quick, with a pinpoint yorker to boot.

With Kaul, Rashid and Shakib doing their bit, Sunrisers went on to defend scores of 118 and 132 against two of the tournnament's most fearsome batting line-ups, bowling Mumbai out for 87 and Kings XI Punjab for 119.

Do these feats make this year's Sunrisers the best T20 bowling team, ever? Not yet. But their patterns are similar to the most successful T20 bowling sides ever assembled. This season, Sunrisers have topped the league in three of the four basic parameters that measure the efficiency of a bowling outfit - wickets taken, economy rate and average - and are second behind Mumbai Indians on strike rate.

Three out of four is pretty good, and almost always correlates to a very successful season. Rising Pune Supergiant - last season's runners-up - topped the league in three out of four parameters too, as did the Bangladesh Premier League's 2017 winners and 2018 runners-up Dhaka Dynamites. The current BBL winners Adelaide Strikers, too, topped in three out of four categories.

However, to be counted among the best bowling outfits in all T20 cricket, a team needs to tick all four boxes, and no IPL team has achieved that. In all, only 11 T20 teams have achieved the grand slam, and all but one (Lancashire, 2015) of those teams have either won or finished as runners-up that season.

South Africa's Cape Cobras attack, which included Dale Steyn, Sunil Narine, Charl Langeveldt and Vernon Philander, managed the feat in the 2013-14 and 2014-15 seasons, when they finished as winners and runners-up of the Ram Slam T20 tournament. Titans, the Ram Slam winners in 2015-16 and 2017-18, did the same, as did the 2017 Pakistan Super League champions Peshawar Zalmi, who had Hasan Ali, Shakib, Samit Patel, Wahab Riaz, Shahid Afridi and Jordan in their squad. Scorchers, too, ticked all four boxes when they won the 2014-15 Big Bash League.

These statistics clearly show a correlation between strong bowling attacks and success in T20 tournaments, reaffirming the wisdom of Mahmood's statement.

With Bhuvneshwar expected to return from injury, Sunrisers' bowling is set to become even stronger. If they keep up their form as a bowling group, it won't be a surprise if Sunrisers repeat their 2016 performance. Whichever way it goes, we'll be keeping an eye on the numbers.

with stats inputs from Shiva Jayaraman

Stats updated until April 27, 2018

Sreshth Shah is a sub-editor at ESPNcricinfo