Holders and leaders Inter have all but won a fourth successive title as they enjoy a 10-point lead over second-placed Juventus with six matches to go.

"It's not as simple as just bringing in two or three champions," Del Piero told Tuttosport.

"There are lots of other factors involved (in league defeat). For example, we played several games at night in the winter this season.

"On these evenings it was very cold or humid, which didn't help and then there were the refereeing errors that influenced results."

Del Piero failed to replicate the form that saw him finish last season as the league's top scorer.

He scored 10 goals so far this season, two behind Juve's top scorer and summer acquisition Amauri.