Liverpool crashed to a surprise 1-0 loss at home to Aston Villa on Saturday, after Chelsea beat Swansea City 4-2 to move clear at the Premier League summit.
Villa striker Gabriel Agbonlahor scored the only goal at Anfield in the ninth minute, hooking home from close range after Philippe Senderos’s header was blocked by Javier Manquillo.
After debutant Adam Lallana and Mario Balotelli shot wide, Liverpool manager Brendan Rodgers sent Raheem Sterling on, but the closest the hosts came to equalising was a shot from Philippe Coutinho that hit the post.
While Villa – who have not lost at Anfield since December 2010 – remain unbeaten this season, Liverpool have now lost twice, following last month’s 3-1 loss at Manchester City, and trail Chelsea by six points.
“I think the players gave everything today,” said Rodgers, whose side were missing injured striker Daniel Sturridge. “We just couldn’t find that quality in the final third of the field and Aston Villa defended well.”
Asked to explain Villa’s victory, manager Paul Lambert told Sky Sports: “Just pure hard work.”
He added: “It is one of the toughest places to come in Europe, let alone Britain, but I think we deserved the win.”
Villa climbed to second, two points behind Chelsea, who came from behind to beat Swansea at Stamford Bridge thanks to a hat-trick by Diego Costa.
John Terry’s own goal from Neil Taylor’s left-wing cross gave previously unbeaten Swansea an 11th-minute lead, but Costa equalised on the stroke of halftime with a header from a right-wing corner.
He struck twice in 11 minutes to put Chelsea in control, polishing off a Cesc Fabregas cut-back and a mishit Ramires shot, and Loic Remy made it 4-1 with a debut goal before Jonjo Shelvey replied for Swansea.
Brazil-born Spain international Costa now has seven goals to his name and is the first player to score in his first four Premier League games since Coventry City’s Micky Quinn in 1992.
“Diego Costa is one of the best strikers we have at this moment in football,” said Chelsea manager Jose Mourinho.
“The team is an attacking team that creates a lot and creates spaces for a striker. It could have been five or six.”
Earlier, Martin Demichelis scored an 83rd-minute equaliser as champions Manchester City held Arsenal to a 2-2 draw in an entertaining encounter at the Emirates Stadium.