Everton have sacked manager Ronald Koeman after they dropped into the relegation zone following Sunday's 5-2 home defeat by Arsenal, the Premier League club said on Monday.

Dutchman Koeman took over 16 months ago and spent a significant amount of money overhauling the squad in the last transfer window, but Everton have won two out of nine league games in their worst start to a season since 2005-06.

"Everton Football Club can confirm that Ronald Koeman has left the club," Everton said in a statement on Twitter.