The defeat leaves the champions only five points clear at the top after a game they really should have won.
“It’s a difficult defeat to digest but it’s part of the game,” Conte said.
“It hasn’t been a performance that we would willingly remember. We were in the lead with 11 against 10. It’s a game which makes you reflect and which will help us get better. It’s annoying to lose this type of game.
“We had some players who were not fully fit but in the next month and a half, we are going to have to grit our teeth. Sampdoria had a bit of luck but I congratulate them.”