England striker Danny Welbeck scored twice at Brighton's Amex Stadium, either side of Milos Kerkez's equaliser for Liverpool in their latest disjointed display under manager Arne Slot on Saturday.
Liverpool have taken just one point from their last three league games.
"It's not good enough, no matter how many excuses I come up with," said Slot, whose position is coming under scrutiny less than a year after leading Liverpool to a record-tying 20th English top-flight title.
Among those excuses might be Liverpool's injury problems, which worsened when striker Hugo Ekitike hobbled off in the eighth minute with a dead leg. Slot said it wasn't serious.
The Dutch coach was already without star winger Mohamed Salah and goalkeeper Alisson Becker, who was hurt this week, while Alexander Isak, their big signing last summer, has been out since December and hasn't been fully fit all season.
Still, few could have expected Liverpool's title defence to be so underwhelming when the club spent a record $A811 million in last summer's transfer window to bolster a championship-winning squad.
Welbeck — the evergreen 35-year-old striker — rose above Ibrahima Konate to nod home the opening goal for Brighton in the 14th minute.
Liverpool responded in the 30th when Kerkez intercepted a headed backpass by Lewis Dunk and flicked a lob over goalkeeper Bart Verbruggen.
Welbeck tapped in the winner in the 56th for a goal that survived a VAR check.
"They were the better team," Slot said of Brighton.
In the relegation scrap, next-to-last Burnley slipped closer to the drop by squandering the lead and losing 3-1 at Fulham.
Josh King, Harry Wilson and Raul Jimenez — with a stoppage-time penalty — scored for Fulham after Zian Flemming put Burnley ahead in the 60th.
It was an emotional afternoon for Mexico striker Jimenez, who was reduced to tears after his first goal since the death of his father last week.
