Spurs were furious with the officials during the game when the Blues were awarded a controversial goal at the start of the second half to give them a 2-0 lead.
Despite Juan Mata's strike being on target, it was clearly in front of the line when it hit a number of bodies.
"Apparently it didn't cross the line. I can understand the frustration, but I don't know how much it would have mattered because we scored five, not two," said Di Matteo.
"Sometimes you get a decision, other times you don't."
Chelsea will return to Wembley in May when they take on Liverpool in the FA Cup final.