Swansea’s winless run in the Championship now stands at eight matches after they lost 2-1 in a scrappy affair at Reading.
City went behind in the 27th minute when Andy Carroll smartly volleyed home, and could have fallen further adrift five minutes later.
Carroll was pulled over by Jay Fulton in the area but Yakou Meite thundered the resultant penalty high over the crossbar.
Tom Ince extended Reading’s lead in the 53rd minute with a low drive for his 100th club goal but Swansea reduced the gap in the 71st minute when substitute Liam Cullen tapped home from close range.
Like Swansea, Reading went into the game just three points off the play-off places in a congested table – and seven points from the relegation zone.
A lively opening saw both sides press forward energetically but neither managed to fashion any clear-cut openings.
Ince led a quick break for Reading and was able to create the game’s first chance with a pinpoint cross into the Swansea area.
It found Carroll in support but the striker could head only weakly at City goalkeeper Steven Benda.
Swansea responded well, with Oli Cooper forcing a fine double save from home keeper Joe Lumley, but Reading went in front three minutes before the half-hour mark.
Benda failed with an attempted punch from Ince’s free-kick on the right and Carroll pounced for his third goal of the season.
Five minutes later, Reading could have stretched their lead after Fulton had clumsily grappled Carroll to the ground.
Referee James Linington instantly awarded a penalty but Meite opted for power instead of precision and blazed it high over the bar.
Swansea opened promisingly at the start of the second half, with Joel Piroe nodding wide from a half-chance.
Just before the break, Piroe had missed a golden opportunity for the equaliser after glaringly missing a searching Fulton cross.
Eight minutes after the interval, Reading doubled their advantage after Swansea had made a complete hash of a short goal-kick routine.
Mamadou Loum broke it up and allowed Ince to curl in his sixth goal of the season from the edge of the area.
But City got back into it 19 minutes from the end, when Lumley could only tip a far-post Piroe header on to a post.
The ball rebounded kindly for Cullen and he had the easiest task to tap it over the goal line.
Yet despite a late rally, Swansea were unable to find the leveller.