After a club record 68-match unbeaten run at home in the league, the champions have now lost back-to-back home matches against Burnley and the Seagulls.
Steven Alzate bundled home the game’s only goal early in the second half to condemn the Reds to a defeat which leaves them seven points off the pace in the title race, and Robertson says the visitors were the better side.
“You have to give the the team credit for playing well. They created chances, pressed us – did everything we wanted to do.
“We didn’t really do anything of note. With a long record of going unbeaten we’ve lost two. When you don’t show up you don’t get results.
“We prepare for every game different. It’s just not clicking. We need to find a way to get results, especially at home. You can do everything in training.”
Liverpool now face league leaders Manchester City at Anfield on Sunday, when a defeat would place them 10 points behind Pep Guardiola’s side.
“Any game against Man City is a big one. As this moment stands, we’re not in the title race,” admitted Robertson.
“We are seven points behind them and they have a game in hand.
“I’m sure they’d say the same if they were potentially 10 points behind. We need to get back to the Liverpool everyone knows.
“We’re still a good team. We don’t turn into a bad team overnight.”