Watford battled to a 1-1 draw against Crystal Palace in the Premier League this afternoon.
Despite struggling to get to grips with the game and going behind in the first half, the Hornets improved producing a determined second half performance to earn a Boxing Day point.
Heurelho Gomes' penalty stop and Deeney's 100th Watford goal cancelled out Yohan Cabaye's opener.
Stefano Okaka and Isaac Success were notable absentees at kick-off, the former not ready to return, the latter left out as a precaution - both with hamstring issues.
It was a disrupted start for Watford at Vicarage Road as Mazzarri was forced into two early changes.
Daryl Janmaat couldn’t shake off a knock after challenging Zaha for the ball, leaving Zuniga to take his place two minutes into the game.
The Hornets' injury problems went from bad to worse when Behrami pulled up with an issue ten minutes later. With the midfielder unable to continue, Deeney was introduced.
With the Hornets struggling to hit their stride, it was the Eagles creating the chances early on.
Benteke had a good opportunity to open the scoring for the visitors after a dangerous cross by Townsend found the Belgian’s head but he was unable to get the necessary contact allowing Gomes to gather the ball comfortably.
Palace’s first real sight of goal came after Prodl dispossessed Benteke, but the loose ball fell to Cabaye who could only shoot wide of the Watford goal from 18 yards.
Moments later the away side broke the deadlock when Townsend provided the through ball for Cabaye to run onto and produce a sweeping finish past Heurelho Gomes.
A poor back pass from Prodl allowed Benteke to knock the ball past an onrushing Gomes, who fouled the Palace forward and presented Benteke with a wonderful opportunity to double their lead from the spot.
However the Watford keeper was equal to Benteke’s effort and kept the score at 1-0 with a save down low to his left.
It was a bright start to the second period as the hosts managed to breach the Palace back four for the first time.
Deeney’s flicked header reached Ighalo inside the 18-yard-box, but under pressure from Scott Dann the Nigerian international could only drill wide.
With 71 minutes on the clock the Golden Boys were given the opportunity to level after Damian Delaney hauled Prodl to the floor in the penalty area, leaving referee Mark Clattenburg with no choice but to point to the spot.
Club captain Deeney stepped up and blasted the ball down the middle of Hennessey’s goal, levelling the score and subsequently reaching a landmark 100 goals for the Hornets.
The Eagles immediately went in search for a second when a Jason Puncheon free-kick saw Dann find space in the area, but the towering defender could only guide the ball harmlessly over.
Good work down the left-hand side from Zuniga and Guedioura saw the ex-Palace man produce a threatening cross that was headed goalwards by Ighalo, but straight at Hennessey.
With time running out Mazzarri introduced Jerome Sinclair to the game, taking Zuniga’s place on the field as the Golden Boys went in search of a winner.
In the final stages of the game, Guedioura managed to create a chance from nothing following a skilful piece of control followed by a volley that was gathered down low by Hennessey.