Abdoulaye Doucoure scored a controversial last-minute equaliser to secure a 2-2 draw for Watford as Southampton's Premier League winless run was extended to 10 matches.
A first-half double from James Ward-Prowse had put the Saints in the driving seat, but Andre Gray cut the deficit early in the second half and Doucoure got the leveller at the death, appearing to use his hand to do so.
It added to Mauricio Pellegrino's misery as his side's poor form continued, though Watford themselves have won just once over same period of Saints' top-flight winless streak.
Having opened his account for the season in last weekend's FA Cup win over Fulham – setting up a fourth-round clash with the Hornets – Ward-Prowse picked up where he left off.
The midfielder broke the deadlock after 20 minutes as Southampton sought revenge for September's 2-0 loss to the same opponents at St Mary's Stadium.
Pellegrino's men continued to impose themselves on the game and, after Dusan Tadic and Wesley Hoedt had been thwarted by Heurelho Gomes, Ward-Prowse was on hand again to cap a swift counter-attack with a straightforward finish.
Watford fought back after the break, with Gray nodding in and Doucoure stealing the headlines in more ways than one, leaving the visitors to wish VAR was in use.
FT | #watfordfc 2-2 Southampton— Watford FC (@WatfordFC) January 13, 2018
Gray and Doucoure goals after the break peg back the Saints, who led via a first-half Ward-Prowse double. #WATSOU
Listen live https ://t.co/MVTxcdM2TV pic.twitter.com/G7X6pENKv4
Southampton threatened early on but saw a promising attack ended by an offside flag as Shane Long's shot forced a reflex save from Gomes.
The hosts badly fluffed their lines to ensure a dangerous foray into the Saints box yielded no reward, with Doucoure's cutback miskicked by Gray before Daryl Janmaat's follow up was blocked, the same player then flashing a powerful drive just over the crossbar.
But, having failed to make that pressure count, the Hornets were punished at the other end when Ward-Prowse coolly slotted home from inside the box after good work from Long.
Gomes came to Watford's rescue to deny Tadic a certain goal three minutes later, the Brazilian pawing away the midfielder's back-post header.
A speculative Hoedt effort from long range gave Gomes yet more work to do and he was equal to it, as was Marvin Zeegelaar when the Dutchman had to block Long's attempt from the edge of the six-yard box.
But there was nobody there to save Silva's side when Long burst down the left to pick out Tadic, who in turn laid on a simple finish for Ward-Prowse.
Troy Deeney was introduced at the interval, marking his return to league action after a four-match ban following his dismissal against Huddersfield Town last month.
A much-improved Watford started to show signs of life early in the second half and Richarlison had a shot blocked before finally they got their reward after 58 minutes.
Janmaat's rasping drive was tipped onto the bar by Alex McCarthy, who got no help from his defence when the ball fell for an unchallenged Gray to nod in.
Molla Wague then mistimed his jump when well positioned to connect with substitute Roberto Pereyra’s delivery as Watford continued to turn the screw.
Pellegrino sent on Mario Lemina as he looked to stem the tide and Southampton did initially stabilise, helping to quieten the expectant home crowd until Doucoure had the final say, turning in Deeney's header across goal and evading the attentions of referee Roger East.
Key Opta stats:
- The Hornets have recovered eight points from losing positions at Vicarage Road in the Premier League this term – only Everton (9) have rescued more on home soil.
- Southampton are winless in their last 10 games in the Premier League; their longest run without a win in the competition since January 2005 (also 10 games).
- Watford have conceded 25 goals at Vicarage Road in the Premier League this season – the most of any side in home games.
- Dusan Tadic recorded his 27th Premier League assist for Southampton in this game – only Matt Le Tissier (64) has made more for the Saints in the competition.
- Southampton conceded their 1000th goal in the Premier League following Watford’s equaliser – becoming the seventh team in competition history to do so.
|Insigne prefers Messi to new Juve star Ronaldo|
|Koepka enjoys playing with a chip on the shoulder|
|Ryan Hall to leave Leeds Rhinos amid reports of NRL move|
|Hamann slams Lahm for Low criticism|
|Hart named in Manchester City squad for United States tour|
|F1 Raceweek: Leader Vettel heads home|
|Unfair to pin Brazil blame on Neymar, says Kaka|
|Thomas and friends ´want to beat each other´s brains in´|
|Woods´ love for links fathered at Carnoustie|
|Confident Rose targets tournament wins and number one spot|
|Hallgrimsson leaves Iceland post|
|Australian Open to consult players over fifth-set tie-breaks|
|Daley´s coming home - Ajax rewrite Three Lions anthem|
|Woods: Open my best chance at winning another major|
|Blind completes Ajax return from Manchester United|
|I belong at the top, says Anderson|
|Leaving Madrid was my biggest regret, Panucci warns Ronaldo|
|Folau in no rush to settle future amid Reds rumours|
|Degenkolb: I need two or three secretaries to manage congratulations!|
|Harrington v Garcia: When winning makes life tougher|
|Mafi and Timani fined by Rebels|
|Watson: Johnson and Woods can prosper at Carnoustie|
|Alderweireld hints at Tottenham departure|
|Maradona takes over as Dynamo Brest chairman|
|The Open 2018: Wounded animal Spieth is a danger to Carnoustie rivals|
|Wests´ Reynolds to miss the rest of 2018|
|Pussy Riot members jailed for World Cup final protest|
|Ronaldo capture boosts Serie A - Mourinho|
|Goals at three World Cups and 50 for the Socceroos – Cahill´s international career in numbers|
|Giroud: It´s coming home|
|Harper wins Home Run Derby in Nationals Park|
|Brighton sign Button from Fulham|
|Bolt set to trial with A-League club Central Coast Mariners|
|Thomas asks Seahawks for extension or trade|
|Walker doubts he´ll join Knicks, wants ´long´ stay at Hornets|
|Socceroos hero Cahill retires from internationals|
|Record income revenue for Barcelona|
|Kudla untroubled as Young bows out in Newport|
|Celtics still hoping to re-sign Smart|
|Villarreal sign highly rated Velez midfielder Caseres|
|Juventus signing Ronaldo should give Milan optimism – Kaka|
|Berrettini masters Mayer in Bastad|
|Manchester United and Ajax agree Daley Blind transfer|
|Familiarity with demands of Real Madrid an advantage – Lopetegui|
|Parmentier rallies to avoid Bucharest exit, Arruabarrena bows out in Gstaad|
|Steelers fail to sign Bell to long-term deal|
|Over 10 per cent of Croatia´s population welcomes World Cup heroes home|
|Thierry Henry quits pundit role to focus on coaching|
|France´s World Cup winners given heroes´ welcome in Paris|
|At the end we will see who is best - Ronaldo sidesteps Messi rivalry|
|Qatar? China? Ronaldo only has eyes for glory at Juventus|
|Proud Kane praises team-mates after Golden Boot win|
|The Open 2018 diary: Is that Tiger Woods? Harrington feels the Burn...|
|Porte targeting Vuelta after Tour de France anguish|
|Maradona madness, #WaistcoatWednesday, bruised Batshuayi - Alternative World Cup awards|
|It could be the best time - Martinez hints at Hazard Chelsea exit|
|England call up Billings as cover for injury doubt Roy|
|McIlroy on track for fitting major haul - Harrington|
|Froome plays down Thomas battle for Sky supremacy|
|Carnoustie record counts for little at The Open, says Fleetwood|
|I don´t see it - Napoli chief De Laurentiis plays down talk of Callejon-Suso swap|
|One or two changes required at Chelsea, says Sarri|
|Monaco confirm Golovin approach|
|Let´s keep making noise! - Serena dedicates Wimbledon run to fellow mothers|
|Full list of Open tee times|
|Fakhar inspires another big Pakistan ODI win|
|Spieth ´annoyed´ by re-watch of 13th hole|
|Kaka claims Ronaldo arrival will boost all Italian clubs|
|Spieth vows to be more artist than tactician in Open defence|
|Conte thanks Chelsea players, staff and fans|