The Spaniard led the Hornets to a mid-table finish, as well as the FA Cup semi-finals, but was shown the door following a subpar showing after the turn of the year.
In comes experienced Italian Walter Mazzarri to steady the Hertfordshire ship and he, like Sanchez Flores was, has been extremely busy in regards to transfers.
Watford made a massive number of signings during the summer but will the new blood settle quickly enough to give a sign that there will be top flight football at Vicarage Road next season as well?
Watford - 2016/17
Talented Argentine who arrives having failed to force his way in at Juventus.
The 25-year-old attacking midfielder managed close to 70 appearances for the Bianconeri after gaining a European education with Udinese.
Formerly of Argie giants River Plate, Pereyra has 10 caps for his country to his name and has the qualities to shine in a free-wheeling role behind the strikers.
A very good signing.
Daryl Janmaat - from Newcastle United for £7m
Has a season of Premier League football under his belt, being one of a few shining lights in a tough season for Newcastle.
Janmaat, 27, is a consummate professional who will provide overlap and attack from the right side of the backline while ensuring he does his job defensively.
The Dutchman is a real leader who will be looked upon by Mazzarri to get the troops together when the chips are down.
Great signing after his stellar campaign for the Magpies and is a fabulous replacement for Allan Nyom.
Isaac Success - from Granada for £12.5m
Signed from the Pozzo family's Spanish interest, Success has all the attributes to bring what his name suggests to Watford.
The exciting Nigerian forward has scored seven times in La Liga and is now expected to be given opportunities to prove himself at Premier League.
The 20-year-old will work closely with compatriot Odion Ighalo in a bid to catch opposition defences off guard.
Could provide glimpses of brilliance but his best is more likely to come a few seasons down the track.
Promising centre-back who was a consistent performer in Belgium with Genk.
25-year-old Kabasele had tallied over 160 senior appearances before moving to Watford, including over 60 in Belgium's top flight.
Can play either side of central defence, which gives Mazzarri some flexibility at the back.
Stefano Okaka - from Anderlecht for £5m
Capable striker who has plenty of experience in Italy.
Okaka joins the Hornets after a decent season at Anderlecht where he scored 17 goals in all competitions.
Has played in both the Champions League and Europa League while being involved in Italian squads here and there since 2014.
The 27-year-old its expected to sit and wait for chances behind Ighalo and captain Troy Deeney but will provide a decent fall-back plan for Mazzarri when those fail to fire.
Younes Kaboul - from Sunderland for £3.5m
The 30-year-old has experienced the Premier League more than 170 times so will bring with him a calmness and composure many of his teammates do not possess.
There are question marks on Kaboul's pace at this stage of his career but his strength and power in the air may yet be handy for the Hornets.
Will share central defensive duties with the hope of imparting his wisdom on the rest of the squad.
Handy addition for nothing who will further strengthen the defensive stocks.
Mariappa, 29, returns to Vicarage Road having already appeared 245 times for Watford, stemming from his first spell which commenced in 2005 and ended in 2012.
The Jamaica international has 87 Premier League appearances to his name and will likely be called upon if there are any shortages at the back.
Brice Dja Djedje - from Marseille for £4m
An odd signing by Watford as he has basically spent all of his time receiving treatment for a calf injury he brought with him from France.
Dja Djedje was not included in Watford's Premier League squad due to his problem, which prompted the signing of Janmaat.
The 25-year-old Ivory Coast full-back will be available for Watford's re-submitted league squad in January but only at the expense of a fellow foreigner.
Would the club have signed him if they knew they were getting Janmaat?
Sinclair has a stack of talent that Watford hope will be nurtured in a competitive environment.
The 19-year-old wanted out at Liverpool in a bid to be played more frequently and although Vicarage Road is a step down from Anfield, there is equal competition for spots.
Ighalo and Deeney have a monopoly on on the first XI while Success will be used when he is fully fit, meaning Sinclair may have to wait for chances again.
Nevertheless, a change of scenery may help greatly after flattering to deceive on Merseyside, despite showing plenty of potential.
Juan Camilo Zuniga - from Napoli on loan
Another depth signing who brings with him the ability to operate as a winger or left-back.
Has an enormous amount of know-how stemming from his 162 Serie A appearances and 61 international caps.
Kenedy - from Chelsea on loan
Sublimely talented youngster who is one of 38 players Chelsea have out on loan this season.
The 20-year-old Brazilian is an intriguing entity as he can be deployed in defence, midfield or attack.
Kenedy has 20 outings for Chelsea to his name, including 14 in the Premier League, and will mainly take a backseat to Jose Holebas at left-back.
Both clubs perhaps hoping Kenedy can emulate Nathan Ake?
It was a busy transfer season for the Hornets who have injected the squad with both youth and experience.
The foundation was already evident from the presence of such players as Deeney, Ighalo, Cathcart, Heurelho Gomes and Ben Watson, Etienne Capoue, and that has now been littered with sturdiness and excitement.
Pereyra and Janmaat are brilliant additions while Success and Okaka makes it a very formidable forward line.
There is much to like about what Watford have achieved over the summer but the swiftness of how these incomers gel will tell the true tale.
Tribal's Transfer Rating: 7.5/10