The defending champions were sluggish very early in each of the two halves of the game and conceded two goals in the process from Sogne Yacouba.
"We had a terrible start and I was shocked. I think my players were sleeping on the field very early in the game and it's unusual," Tandoh said.
"We recovered and pulled one back in the second half but the harm had already been caused that's why we lost. Nobody expected such a poor performance initially but all is not lost," he added.
Tandoh also promised that Aduana will attempt to win their four outstanding games as they try to successfully defend the title.
"We've been unimpressive somehow but there is an opportunity to close up on leaders Medeama. We have four games to play and will try to win all of them in order to successfully defend the title we won last season," he said.
They will then travel to Wa to lock horns with Wa All Stars on June 17 before completing it with a home game against Hearts of Oak on June 24.