Massimiliano Allegri conceded Lazio were worthy winners of the Supercoppa Italiana after his Juventus side were beaten 3-2 in a breathless finale at the Stadio Olimpico.
Ciro Immobile won and converted a first-half penalty before heading his second of the game in the 54th minute to put Simone Inzaghi's men firmly in control.
But there was another sting in the tail as Jordan Lukaku raided down the Juventus right and teed up fellow substitute Alessandro Murgia for the winner.
FT - Lazio clinch the with an injury-time winner. August 13, 2017
"We got in the game in the final half-hour," he Juventus' official website. "I knew we could have trouble, but especially in the first half we did not play.
"Then we started to play with width, to better cover the field, but we had to do that from the beginning.
"We put them under pressure when they got tired. Football sometimes takes away what it has given you other times.
"I am sorry to lose like that but it is not an excuse for our bad performance."
Juventus begin their bid for a seventh consecutive Serie A title at home to Cagliari next weekend and Allegri hopes defeat in the capital will act as a wake-up call.
"In the championship we will not and cannot be the same," he added. "This defeat brings us back to the ground. Winning is not easy.
"Some of us are not yet in shape. I knew it would not be easy. The season has just begun and it will certainly not be a simple one but we will see a different Juve, starting from Saturday."
