Juve were 11 points off the pace on Oct. 31 but took76 points from their next 26 matches to clinch a record fifth consecutive Italian title.
"I think it will be almost impossible to repeat our run," Allegri told reporters.
"Even after some tricky opening matches where we were disorganised and the ball refused to go in, we set some objectives and the team has surpassed them."
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Allegri said lessons were learned from Juve's dismal start to the campaign where they took one point from three games.
"What happened early in the season must teach us that nothing can be taken for granted," he added.
Sampdoria were sunk by two goals from Paulo Dybala, one a penalty, and strikes by Patrice Evra, Giorgio Chiellini and Leonardo Bonucci.
(Writing by Ed Dove; Editing by Tony Jimenez)
