Juventus clinched their sixth successive Serie A title, and completed a third league and cup double in a row, when they beat relegation-threatened Crotone 3-0.
Mario Mandzukic scored from close range after 12 minutes, Paulo Dybala curled in a stunning 25-metre free kick before halftime and Alex Sandro scored late in the game to give them the three points they needed.
Juve are four points clear of Roma with one match each to play.Allegri's "mad idea" ensures another Serie A title for Juve.
The key moment in Juventus's Serie A title-winning campaign came a few days after a 2-1 defeat to Fiorentina in mid-January when coach Massimiliano Allegri had what he described as a "mad idea".
Although Juventus were top of the league at the time, they were only one point ahead of Roma and had already lost four games.
Teams had begun to figure out how to exploit their defence and they were invariably leaving at least one of Juan Cuadrado and Mario Mandzukic, two of Serie A's most gifted forwards, on the bench.
At a training session two days before the following game against Lazio, Allegri said it suddenly dawned on him that he needed something new.
"I am not much of a theorist but every now and then I come up with a mad idea and try it on the pitch," he said.
"During the week I had not even thought about it but after a training session the next morning I thought, 'I have to change something'."
Allegri decided to field all four of his attacking players at the same time with Gonzalo Higuain as a centre-forward, Paulo Dybala behind him and Cuadrado and Mandzukic on the flanks.
It paid off instantly. Juventus scored twice in the first 20 minutes to beat Lazio 2-0 as they began a run of seven successive wins.
They lost only once more, against Roma last week after coach Massimiliano Allegri rotated his team, before wrapping up their sixth title in a row today.
Although it appeared as if Allegri had thrown caution to the wind, his tactics also strengthened the defence and Juventus have conceded only 10 goals in 18 games since then.
Mandzukic, described by Allegri as having "a battery that never runs out", has been a key part of their success. He can be used as a target man, he can charge down the left wing and he also tracks back, often making important tackles in the left-back position.
"The formation doesn't count as much as the attitude with which you play," said Allegri. "If those who play up front also help defensively then you control the match better."
The new formation also allowed Juventus to benefit more from the passing ability of Miralem Pjanic as he was fielded alongside Sami Khedira in front of the defence.
Pjanic, signed from Roma for 32 million euros, has proved a more than able replacement for Paul Pogba even if Allegri has publicly said that he feels the Bosnian could produce more.
“Pjanic sometimes he does these tiny little five-metre passes that drive me mad," said Allegri.
Juve's other new signings also paid off.
Higuain, who became the world's third most expensive player when Juventus paid Napoli 90 million euros for him, repaid the investment with 24 goals while Dani Alves enjoyed a second wind at the club after being let go by Barcelona.
The defence, centred on Giorgio Chiellini and Leonardo Bonucci, remained one of the stingiest in European football and when all else failed, there was always 39-year-old goalkeeper Gianluigi Buffon, who had another outstanding season.
“Gigi deserves the Ballon d’Or," said Allegri. "He deserved it in previous years too, having won so many titles and the World Cup.”