Defeat at Brentford was a fourth on the bounce in the Premier League for the defending champions.
"We've got to work harder, it's as simple as that," Robertson told Liverpoolfc.com. "In training and games; recovering better. All of us have to.
"When you're at this football club, people demand results. The fans travel up and down, I guarantee quite a lot of them in the away end were in Frankfurt as well. They spend a lot of money to come and support us.
"In a difficult moment, the only way to get out of it is work even harder, run that bit more and look after yourself that bit better. That's what we've got to do - because the results have been nowhere near good enough over the last five, six games, and we're the only ones who can get us out of it.
"We know that and starting Wednesday again, there's no rest. There's no time to regroup, we've got games, games, games. Sometimes it can be a good thing that you have got such a quick turnaround and we can go again.
"But we need to start playing better and we need to start showing a lot more consistency in our game."
Robertson also said: "You have to fight for the control. Nobody is going to just say, 'On you go, you take the ball and we'll try to defend.' Nobody does that.
"They always have a game plan against us. All the managers in the Premier League are so talented, especially teams that have had a full week to prepare. They would have had a clear game plan and you'd have to ask their manager but I think they played theirs perfectly - and we didn't play ours at all. That makes it so difficult."