Gracia's departure was announced on Sunday (AEST) with the Hornets bottom of the Premier League table after taking one point from four games.

He led Watford to the FA Cup final and an 11th place finish in the Premier League last term but was dismissed despite captain Troy Deeney publicly backing him to continue.

Watford wasted no time in announcing the club's former coach Flores will be back in the dugout at Vicarage Road for its game against Arsenal after the international break.

Flores spent the 2015-2016 season in charge of Watford, leading it to the FA Cup semi-finals and a mid-table league finish.

Since leaving the Hornets, he has had spells at Espanyol and Chinese Super League side Shanghai Shenhua.

Flores's return is the 11th coaching appointment made by Watford since Malky Mackay's departure in June 2011.

Walter Mazzarri and Marco Silva, who is now in charge of Everton, are among their recent bosses.

Watford's poor form dates back to the end of the 2018-2019 season, which it finished with three straight defeats.

"Javi has represented Watford with great dignity and will always be deserving of our fullest respect for his achievements," Hornets chairman and chief executive Scott Duxbury said.

Deeney had suggested in a recent interview that Gracia should be given time to turn the team's fortunes around.

"The manager is a big boy, he knows what he's doing — it's just part and parcel of the game," Deeney said. "People are always going to question the manager if we've lost a few games.

"It doesn't just happen at Watford, it happens everywhere, but the high turnover of managers at Watford was four or five years ago. Everyone thinks every year we change the manager and get a new one. We are trying to settle down."