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.
|Thomas turns down Celtics´ video tribute|
|Moyes unaware of Chelsea interest in Carroll|
|Verdi wants Bologna stay amid Napoli links|
|Ronaldinho retires – A shining light of Brazil´s 2002 World Cup-winning team|
|Ronaldinho retires – a World Cup and Ballon d´Or among Brazil great´s prizes|
|Celtics great White dead at 71|
|World Cup glory and Bernabeu magic - Ronaldinho´s best moments for Barca and Brazil|
|Trust the Process – 76ers only behind Warriors and Cavs in merchandise sales|
|Ligue 1 Review: Balotelli at the double as Payet shines and Malcom toils|
|Pato still dreaming of World Cup selection|
|FA Cup Review: Iheanacho makes VAR history, kit confusion reigns|
|Wallaby saves wallaby: Farr-Jones in Sydney Harbour Bridge rescue mission|
|2016-17 UEFA Study: PSG, Man City drive record-breaking spending|
|Conte packing in homework as Chelsea games stack up|
|2016-17 UEFA Study: The headlines in transfers, wages and revenues|
|2016-17 UEFA Study: Manchester United record highest revenue but largest debt|
|Monaco stay perfect, Murcia overcome Oldenburg|
|Iheanacho scores English football´s first VAR goal|
|Materazzi not surprised by Coutinho transfer fee|
|Ronaldinho retires - Brazil and Barca great plans 2018 farewell|
|Jags RB Leonard Fournette uninjured in three-car accident|
|India revenge would heal Proteas´ scars - Elgar|
|Koziello swaps Nice for Cologne|
|Simeone ready to unleash Costa and Vitolo alongside Griezmann|
|Head coach Cooper to leave Stade Francais|
|Silverwood plays down talk of replacing Bayliss|
|Lambert ´never thought´ he would return to Premier League|
|Wenger ´very aggressive´ towards referee Dean, says FA report|
|Reported Arsenal target Malcom starts for Bordeaux vs Caen|
|Valverde not making big deal of Dembele´s latest Barca blow|
|Costly day for Kohli as Proteas close in on series win|
|Date set for Afghanistan´s maiden Test|
|Returning McIlroy ready to end winless run|
|In-form Short leaves coach Kirsten needing dental treatment|
|Arsenal will have a ´hard time´ signing Malcom|
|Ronaldo and Madrid nominated for Laureus awards|
|Nantes´ Diego Carlos brands Chapron clash ´historic´|
|This is not important - Conte unconcerned if substitutions upset Hazard|
|Conte ´doesn´t think´ Chelsea have pursued Sanchez|
|Cobblestone climb part of 2019 Tour de France Grand Depart|
|Emery hints at Neymar return against Dijon|
|Joshua labels Parker claims ´fake news´|
|´Emotional´ Fleetwood honoured by Seve Ballesteros Award|
|Tears for Kvitova as Bouchard sets up Halep meeting|
|Mkhitaryan key to United-Sanchez deal, claims Raiola|
|WATCH: Sabalenka wins point using racquet throat|
|Federer, Djokovic and Zverev among Australian Open first-round winners|
|Kubica gets reserve role as Williams hire Sirotkin|
|Shambolic Stars out after Sixers thrashing|
|Wales pick uncapped Worcester wing Adams in Six Nations squad|
|Tevez: CSL spell was a holiday|
|Mignolet considering Liverpool future|
|Laidlaw among several returning stars in Scotland Six Nations squad|
|´Fairy tale´ 2017 motivation for Federer|
|Fred waiting for Guardiola call amid Man City speculation|
|Dominant Federer makes light work of Bedene|
|Halep faces nervous wait over ankle injury|
|Inter confident but patient over Rafinha|
|Kohli fined after umpire outburst|
|Djokovic hits back at Australian Open boycott suggestions|
|De Grandhomme lifts Black Caps to win in Taylor´s 200th ODI|
|Giggs had counselling after Old Trafford exit|
|Durant continues dominance over Cavs as Warriors win|
|Halep survives scare and rolled ankle at Melbourne Park|
|Westbrook ejected against Kings after arguing call|
|Djokovic eases past Young on return|
|Sharapova staying grounded after Melbourne win|
|Neville: Mourinho would happily swap Mkhitaryan for Sanchez|
|Raonic suffers surprise loss in Melbourne|
|Sharapova wins on return to Australian Open|