Watford are the first Premier League club to make a managerial change this season.
In a rather shock decision, the Hornets parted company with Javi Gracia on Saturday afternoon just four months after guiding them to an FA Cup final, although supporters didn't have to wait too long his replacement to be announced.
Former boss Quique Sanchez Flores is back at Vicarage Road.
Watford are the only Premier League club yet to register a win in the league this season, and have picked up just one point in their first four league games, a 1-1 draw with Newcastle United in the match before the international break.
Sanchez Flores had a successful first period at Watford, leading the club to a comfortable Premier League finish and an FA Cup semi final in their first season back in the league.
The Spaniard won 16 of his 44 games in charge of the Hornets over the 2015/16 season.
Sanchez Flores' first game back in charge of Watford sees Arsenal and Unai Emery visit Vicarage Road.
The two managers have met on seven previous occasions, with the new Watford boss coming out on top more often than not.
In fact, out of the seven meetings, Sanchez Flores has won three times, while Emery has emerged victorious on just one occasion.
The other three encounters have ended in draws.
Arsenal will go into the game expecting to take the three points, especially considering the start to the season that both teams have had, however, some that often comes with a new appointment.
The managers will meet again for the eighth time on Sunday 15th September at 4:30pm.