Liverpool's defensive gremlins returned again as their Premier League title ambitions suffered a painful body blow in a 3-2 home defeat by relegation battlers Swansea City.
Manchester United also dropped precious points in their top-four push, although Wayne Rooney celebrated breaking Bobby Charlton's all-time scoring record for the club with a superb last-gasp free-kick to salvage a 1-1 draw at Stoke City.
Rooney, on as a substitute, curled home his 250th United goal after Stoke had led for more than 70 minutes thanks to an own goal from Juan Mata. United remained in sixth spot.
"It means a hell of a lot. It is a great honour and I am very proud," Rooney said. "It is difficult at the minute to be over-pleased because of the result but in the grand scheme it is a huge honour."
Gylfi Sigurdsson's 74th-minute winner ended Liverpool's 17-match unbeaten league run at Anfield and left Juergen Klopp's side seven points behind leaders Chelsea, who play on Sunday.
Precious little happened in a goalless first half at Anfield but Swansea, who began the day bottom, silenced the Kop when Spanish forward Fernando Llorente toe-poked home two minutes after halftime and headed in another five minutes later.
Liverpool retaliated, two goals by Roberto Firmino dragging them back, the first a header from James Milner's 55th-minute cross and the second a sumptuous half volley.
Klopp's side were the first top-flight side to score 50 goals this season but their defensive deficiencies again proved a thorn in their side as memories of a 4-3 defeat at Bournemouth in December came flooding back minutes later.
A Liverpool victory had looked the most likely outcome with half an hour left but Swansea had other ideas and from a rare foray forward the ball fell to Sigurdsson and the Icelander put the Welsh side back ahead.
Liverpool could not respond, leaving Klopp crestfallen.
"The most disappointing moment was the third goal and I can't explain it as we had so many chances to challenge," the German said.
"It's really difficult to accept at this moment. It is fair Swansea won, no - but was it deserved, yes."
Improving West Ham United won for the fifth time in seven league games to move into the top half - Andy Carroll again on target with two goals in a 3-1 victory at struggling Middlesbrough.
Sunderland sunk to the bottom after a 2-0 defeat at West Bromwich Albion for whom Darren Fletcher and Chris Brunt were on target.
Bournemouth drew 2-2 with Watford and Crystal Palace ended the day in the bottom three for the first time this season after a tame 1-0 home defeat by Everton, Seamus Coleman thumping home a late winner.