Arne Slot slammed Liverpool's performance after their perfect start to his reign came crashing to a halt with Saturday's surprise 1-0 defeat at home to Nottingham Forest.
Callum Hudson-Odoi's deflected second-half strike proved decisive as Forest earned their first league victory at Anfield in 55 years, having last triumphed on the ground against Bill Shankly's Reds in 1969.
Liverpool's 14 shots throughout the game gave them a total expected goals (xG) figure of just 0.87, with only five of those attempts forcing Matz Sels into action.
The Reds boasted a 69.6% possession share but only marginally beat Forest's 56 final-third entries with 70 of their own, leaving Slot to bemoan their lethargic play in possession.
"The result frustrates me the most and we cannot be happy about how the game went. It was a stop-start game and we hardly created any chances," Slot told BBC Sport.
"We only have to look at ourselves, we have to be better. Far too many times we lost the ball around the area, it was not good enough. We have to be better with the ball.
"Our decisions and execution weren't good enough.
"In general, we defended quite well but the two fast players came on and made it difficult for us. We took a lot of risks and in the end it was a very good goal."
Liverpool have now lost two of their last five Premier League matches at Anfield (three wins), having only lost one of their previous 58 before this run.
Forest, meanwhile, have won four straight away Premier League matches for the first time since 1995, and they sit just one point behind Liverpool in the early-season standings.
Boss Nuno Espirito Santo was delighted with their defensive work, telling BBC Radio 5 Live: "Liverpool are such a good team, it required a lot of effort from the players... the organisation, tackling and the covering.
"The only way to achieve anything here is if you are organised and do everything that you can.
"When you start the way we started with our wingers, Nico Dominguez and Elliot Anderson – all the effort of them tracking Liverpool's full-backs, it is a lot of energy.
"We are working hard and it is about building and believing in this idea that you can develop."