Swansea City's decision to sack manager Paul Clement reflected the mounting anxiety in the Premier League's lower reaches as the frenetic festive period begins.
He took over at Swansea in January, replacing Bob Bradley, with the club bottom of the Premier League and tipped as odds-on favourites for relegation.
Sigurdsson's stunning goal against his former club maintained Everton's unbeaten record under Sam Allardyce with a 3-1 win.
Swansea ended its losing streak in the Premier League with a 0-0 draw against Bournemouth on Saturday but failed to ease the pressure on head coach Paul Clement.
Portuguese Sanches joined Swansea City on a season-long loan move from Bayern Munich, the English Premier League club announced Thursday.
Swansea can now decide their own destiny in the Premier League, with two league games left to play this season.