Jurgen Klopp has said Liverpool are still in "preseason" mode despite winning all four games in their Premier League campaign so far.
Liverpool are unbeaten this season after an interrupted summer, where a number of players missed large parts of preseason because of the World Cup.
Klopp put his players through double training sessions in the build-up to the recent win at Leicester City in an effort to get his side in a better physical condition ahead of the start of the Champions League group stages.
"The players are not at their top level yet," he is quoted as saying in the Daily Mirror. "That is because we are in the early part of the season. It is normal.
"Everybody should know we have a lot of work to do still, but if they don't then I have told them. When you win four times it sounds really crazy to say this, but it is still part of the preseason for a very long time after the summer.
"From mid-September, we play every three days. So we do the work now, and this is how it is -- it is normal that you are not quite at 100 percent in the games."
Liverpool return to action after the international break on Sept. 15 when they play Tottenham at Wembley, before hosting Paris Saint-Germain at Anfield three days later to kickoff their Champions League campaign.
Meanwhile, Liverpool captain Jordan Henderson has told Sky Sports that he believes Joe Gomez can reach whatever level he desires in football.
Gomez, who has drawn plaudits for his start to Liverpool's season at centre-back, is back in Gareth Southgate's England squad after being forced to miss the World Cup with injury.
"He's already very good, but he can be even better," Henderson said. "He's still very young, he's still improving, learning.
"There's no better place to do that than at Liverpool with the players that he's got around him and the manager.
"Also here [at England] it's a fantastic environment with the players, staff and manager. It's a fantastic environment for him to bring that form into England and show how good he is against the best players in the world. So I'm excited for him because I know how good he can be.
"He's got the right mentality as well. He's very mature for his age, his feet are firmly on the ground and he can be as good as he wants to be."