Alisson warned Liverpool cannot make excuses for their below-par performance against Leicester City as they target an improvement at Brentford.
Two calamitous own goals from Wout Faes gifted the Reds a 2-1 victory over the Foxes at Anfield on Friday – their fourth consecutive win in the Premier League.
However, Jurgen Klopp's men were criticised for their display, having fallen behind to Kiernan Dewsbury-Hall's early goal and looked vulnerable at the back.
Liverpool have an opportunity to move ahead of fifth-placed Tottenham when they visit the Brentford Community Stadium on Monday, and Alisson goalkeeper knows they need to do better.
"The only thing we could take from Friday was the win and the effort we put on the pitch," the Brazil international told LFC TV.
"But there's a lot of space to improve. Looking at the performance, we have to do a lot better if the ambition is to keep achieving the goals that we have in front of us.
"We have high expectations and the supporters have high expectations about us.
"Liverpool is a huge club which will always try to fight for titles and to be there at the top all the time. We have to do more, but we know that.
"We cannot rely on excuses. It was only the second game we have played after the World Cup. The players who had time off used that to prepare themselves. The ones who went to the World Cup could train and then rest to prepare for this moment.
"It's going to be a really important moment of the season now and we have to focus. We have to do better.
"Sometimes it's just a matter of mentality. It's not that easy to change it but we can do that for sure."
Liverpool have scored three or more goals in each of their past five meetings with the Bees.
The Reds have only scored three or more goals in six consecutive games against the same opponent once, versus Fulham between 1986 and 2000.