Watford conceded in the 99th minute to fall to a 3-2 defeat away at promotion-chasing Southampton despite intially responding from being two goals down.

The hosts had the perfect start when Will Smallbone headed home inside the first minute, and extended their lead soon after when Ché Adams capitalised on a poor clearance.

The Hornets grabbed a goal back before the break through Ryan Porteous, and drew level when substitute Ismaël Koné coolly finished.

However, there was heartbreak when Flynn Downes converted from a corner at the death, condemning the side to a first defeat under Tom Cleverley.

The game got off to the worst possible start for the Hornets, with the side a goal down with fewer than 60 seconds on the clock. An Adam Armstrong cross from the left found Smallbone unmarked in the box, with the midfielder heading home from close range.

Looking to respond, Watford’s first chance of the afternoon fell to Giorgi Chakvetadze, but his effort following a driving run through the middle was easily claimed by Gavin Bazunu.

Smallbone had a chance to double the lead when he dispossessed Tom Dele-Bashiru on the edge of the box, but couldn’t keep his shot down after a quick one-two with David Brooks.

However, Southampton did make it two soon after. The Hornets were unable to clear Kyle Walker-Peters' cross, allowing Brooks to cut the ball back to Adams, who had an easy finish to increase the home side’s advantage.

Watford, needing a way back into the game, did enjoy a spell of pressure after conceding the second, twice going close through Yáser Asprilla. First, a cross-field ball from Emmanuel Dennis found the Colombian towards the right of the box, but his attempted curled effort was deflected behind.

Soon after, a special piece of dribbling saw the forward take the ball past several defenders in the box before firing off a shot from just in front of the byline, but the slightest touch from Bazunu ensured it went wide.

The Hornets had their tails up, and capitalised by pulling a goal back. Porteous, forward from right-back, fired towards goal from just inside the box and it made its way beyond Bazunu thanks in part to a Jack Stephens deflection.

Southampton recovered well after conceding and were able to wrangle back some control, meaning the Golden Boys struggled to build on the goal’s momentum. There was action at both ends on the stroke of half-time with Dennis heading over from a free-kick, whilst Armstrong fired over from inside the box immediately after.

Porteous continued his attacking intentions after the break, going close twice in quick succession to finding his, and Watford’s, second. Chakvetadze lofted a ball towards the penalty spot in line with the Scotsman’s run, but his header resembled a defensive one as he failed to direct it towards the goal.

The defender was then able to get a better hold of a header quickly after from a Jamal Lewis cross, directing his effort goalwards beyond the reach of Bazunu, but Taylor Harwood-Bellis was there on the line to prevent the equaliser.

Watford continued to knock on the door as time wore on, enjoying long periods of possession as they searched for the leveller.

For all the pressure, chances were of short supply. Asprilla had an effort blocked from the inside of the area as the Saints continued to hold on.

However, Watford did eventually find the breakthough their second-half performance deserved thanks to a little bit of Canadian excellence.

Introduced from the bench, Koné received the ball midway through the Southampton half and drove into the box, calmly slotting the ball through Stephens' legs and into the far corner to restore parity.

Southampton knew only a win would truly reignite their feint hopes of automatic promotion, and went close through Armstrong and Jan Bednarek, with the latter's header deflected behind for a corner in the seventh minute of stoppage time.

The corner was controlled at the back post by Downes, who then poked it across the line to hand all three points at the death to Southampton.

The result sees Watford sit 15th in the Sky Bet Championship.