Wayne
Rooney had scored his first home league goal of the season, from a
harsh penalty decision, in time added on of the first-half.
However, he blotted his copybook when he conceded a free-kick nearly 25 yards from goal in the 78th minute.
Free-kick
specialist Sigurdsson duly delivered with a superb curling effort into
the top corner that left United keeper David de Gea rooted to the spot
and denied Jose Mourinho a victory that would have lifted United into
third place, temporarily at least.
Instead
they trail fourth-placed Manchester City on goal difference and could
fall three points behind them if City beat struggling Middlesbrough
later on Sunday.
Swansea, who have
righted the ship a little in taking four points from their last two
games after a return of just a single point in the previous six, trail
fourth from bottom Hull by two points with three matches remaining.
Rooney
struck in first-half injury-time after a contentious penalty award by
referee Neil Swarbrick who judged keeper Lukasz Fabianski had brought
down Marcus Rashford when diving at his feet.
Replays
suggested Swansea had been hard done -- Rashford making the most out of
minimal contact -- but Rooney made no mistake with a clinical
conversion from the resulting penalty.
It
was a cruel end to a strong showing by Swansea and a slow start from
Mourinho's side was exacerbated by an injury after just seven minutes to
England left-back Luke Shaw who appeared to damage his ankle off the
ball.
The tactical reshuffle that
followed hardly helped United settle as they struggled to cope with an
impressive and committed opening from the relegation-troubled visitors.
Indeed, Paul Clement's side should have gone in at the half-time interval in front.
On
12 minutes, Ayew's shot was blocked by Eric Bailly who blasted his
clearance directly at Sigurdsson and watched, relieved, as the ricochet
flew harmlessly behind.
Then Fernando Llorente beat Bailly far too easily and was only denied by a flying stop from de Gea.
United
had given Fabianski something to think about, starting in the 16th
minute when Anthony Martial picked out the well-timed run of Jesse
Lingard with a pass which the youngster volleyed too close to the
Swansea keeper.
Martial
was looking increasingly dangerous as he cut in from the left and a
grateful Fabianski smothered his shot at the second attempt as Lingard
was poised to net the rebound.
And before
United would take the lead, there was a reminder that Swansea posed a
real threat as Tom Carroll found Ayew whose shot was blocked by the
outstretched leg of de Gea with the loose ball flying within inches of
two Swansea attackers.
Rooney should have
handed United a much-needed two-goal cushion early in the second half
as he exchanged passes with Ander Herrera but succeeded only in striking
his effort directly into the back of Martial from eight yards.
Mourinho's
mounting injury list grew when the impressive Bailly limped out of the
game with what looked like a hamstring problem on the hour mark.
As
Clement chased the game, Swansea also ran into injury problems with
substitute Jefferson Montero managing to survive just six minutes before
being stretchered off.
Even after their
equaliser, Swansea still pushed for a winner, however, and Llorente
should have done better than mis-kick close to goal from another
threatening Sigurdsson set-piece.
