FA Cup defending champions Arsenal were bundled out of the competition by Watford. Goals from Ighalo and Guedioura condemned the Gunners to a defeat leaving them with only the Premier League and Champions League to fight for.
The Gunners are already one foot out of the Champions League and are eight point behind league leaders Leicester City in the Premier League with just nine games remaining.
Anthony Martial rescued Manchester United with a late equalizer after West Ham United went ahead thanks to a spectacular 30 yard free kick from Payet about 20 minutes into the game. This means the two teams will have to face off at the Upton Park for a rematch as Watford awaits to know who their next challenger will be in the semi finals.