The Spanish outfit had the best defensive record in Spain last season, but they have conceded five goals in their last two games in all competitions.
It has been a mixed start to their league campaign, meanwhile, with two wins and two draws from their first four games.
"It isn't normal to concede five goals [in two matches] but we are working hard to correct what we have done wrong in these two games, and it probably won't happen again," he told reporters.
"Some important players have left the club, and it is normal that when the software on the computer has changed, it takes time for [the computer] to react.
"We have played some great games against [Real] Madrid, and ones not so good like against Eibar. It was always going to happen early in the season, but in two or three matches' time, we will start winning again."
Atletico drew 2-2 with Celta Vigo at the Vicente Calderon at the weekend.