The Hornets began the new Premier League season with a credible point away against Southampton, as Nathan Redmond's strike in the 58th minute cancelled out Etienne Capoue's first Watford league-goal in the first-half.
Ben Watson was shown a red-card with 15 minutes left to play but the Hornets held on to secure a point on opening day.
Walter Mazzarri opted for a 3-5-2 formation for the first game of the new campaign, with Heurelho Gomes starting in goal, behind a back three of Craig Cathcart, Sebastian Prödl and Miguel Britos.
The wing-back positions were filled by José Holebas and Nordin Amrabat, who operated either side of a midfield three consisting of Valon Behrami, Adlène Guedioura and Capoue.
Captain Troy Deeney and Odion Ighalo led the line for the Hornets.
The game started at a frantic pace and the Saints almost took the lead with a minute gone as Dušan Tadic's free-kick was parried wide by Gomes. The Hornets' shot-stopper did excellently to get up quickly and knock the ball away after it had deflected off of Britos. Virgil Van Dijk was alert to follow up, but his effort went harmlessly wide.
With their first effort on target the Hornets were ahead. With nine minutes gone Amrabat whipped a fantastic ball in from the right which Deeney knocked down into the path of Capoue. The Frenchman fired in on the volley for his first competitive goal. The sold-out away section showed their delight as they bounced away behind Gomes' goal.
The Hornets looked extremely comfortable offensively, with Holebas and Amrabat both making an impressive impact down either flank. The latter saw a shot go wide of Fraser Forster's goal with 13 minutes played.
The hosts fashioned another half-chance with 26 minutes on the clock, but James Ward-Prowse's shot from distanced went wide of Gomes' far post.
Shane Long spurned a good opportunity to draw the Saints level just past the half-hour mark, but his header from Tadić's cross was off-target.
Holebas continued to look lively down the left for Mazzarri's side and his cross from out-wide almost found the back of the net, but ultimately flew just over the bar.
The Hornets had to remain alert as Southampton created an excellent opportunity to draw level. Ward-Prowse drilled a ball into the box which evaded everyone inside the area but Cathcart did well to clear the ball from danger.
With the final chance of the first-half, Gomes again did well as he tipped Cédric's powerful effort from distance away from Southampton players who were ready to pounce.
The second-half started in similar fashion to the first with Ward-Prowse just seeing his effort deflect wide of goal and out for a corner.
The hosts continued to apply pressure and were on the front foot. Redmond was a constant threat and he was just unable to get onto the end of Tadić's cross at the far-post.
Soon after and the Hornets found themselves in a good position on the break but Amrabat's tantilising ball into the box just evaded the lurking duo of Ighalo and Holebas.
The Saints would have levelled but for a smart finger-tip save from Gomes to deny Redmond.
The resulting corner into the box fell to Redmond but his goal-bound effort was blocked excellently by Holebas and diverted out for another corner-kick.
Redmond finally got his goal. Gomes came to punch but the ball fell invitingly to the Saints' front-man who hit a first-time volley into the bottom corner.
The home side continued to look lively and almost went ahead shortly after drawing level as Maya Yoshida narrowly headed Steven Davis' free-kick over the bar.
With 63 minutes played, Mazzarri opted to make his first substitution of the afternoon with Ben Watson coming on in place of Behrami at the heart of the Hornets' midfield trio.
A few minutes later, Guedioura stormed through the middle of the park and played in Deeney who fed the ball wide to Amrabat. The full-back's testing pass into the box however evaded everyone when only a touch would have put the Hornets ahead.
The Golden Boys made their second change of the afternoon with 73 minutes on the clock as Juan Camilo Zúñiga made his debut, coming on in place of Guedioura in midfield.
Things took a turn on 75 minutes as the Hornets were reduced to 10 men. Southampton broke quickly from a Watford corner and Watson was left chasing speedster Long as he stormed towards Watford's goal. The midfield man had little option but to halt Long's run and referee Roger East had no hesitation in producing the red-card.
Mazzarri made his final change of the afternoon as Ikechi Anya came on in place of front-man Ighalo as the head-coach looked to tighten-up at the back.
The hosts thought they had taken the lead but Redmond's effort was ruled out for off-side, much to the frustration of the home-faithful.
It would prove to be the final chance of a tense finale to the Hornets' first league game of the new Premier League season, and they travel back to Hertfordshire with a hard-earned point.
HORNETS: Gomes (GK); Britos, Prödl, Cathcart; Holebas, Behrami (Watson, 63), Guedioura (Zúñiga, 73), Capoue, Amrabat; Deeney, Ighalo (Anya, 80)
Subs not used: Pantilimon (GK), Nyom, , Sinclair, Vydra
Goals: Capoue (9)
Yellow cards: Guedioura (59), Gomes (86)
Red Cards: Watson (75)
SAINTS: Forster (GK), Cédric (Pied,79), Yoshida, Long (Austin, 82), Davis, Tadić, Romeu, Ward-Prowse (Emile-Højbjerg, 54), Van Dijk, Redmond, Targett
Subs not used: McCarthy (GK), Clasie, Fonte, Rodriguez
Goals: Redmond (58)
Yellow cards: Van Dijk (90+3)