This is the first time Watford have scored more than once at home in a Premier League game since April 2007 (4-2 vs Portsmouth).
Ighalo is the first Watford player to score two braces in the Premier League.
After James Collins’ red card, West Ham have received the most red cards in the Premier League this season (4).
Ighalo has now been involved in each of Watford’s last nine Premier League goals (seven goals, two assists).
This was West Ham’s first defeat at Vicarage Road since April 1985, having been unbeaten in 11 games at the ground since then (W8 D3).
The Hammers lost their first away game since the last day of last season (2-0 vs Newcastle).