Watford set up an Emirates FA Cup fourth-round replay at St Mary’s following a 1-1 draw at home to Southampton.

The Hornets raced into the lead in the fifth minute when pinpoint accuracy from Matheus Martins saw the Brazilian fire in Watford’s first free-kick goal for 477 days.

However, a late resurgence from the visitors saw substitute Stuart Armstrong curl in an equaliser just before stoppage time to maintain the Saints’ club-record unbeaten run, and set up another meeting between the two sides in the week from next.

Valérien Ismaël opted for six changes from Saturday’s 1-1 draw away to Bristol City, with defender Mattie Pollock making his first start of the season. The returning Emmanuel Dennis took a place on the bench alongside Ken Sema, who has recovered from injury.

Early alertness from Giorgi Chakvetadze saw him intercept a weak Saints pass before releasing Yáser Asprilla, with Mason Holgate hauling down the Colombian on the edge of the area, earning a yellow card in the process.

The free-kick was in a dangerous position, with Martins, thinking quickly after noticing a gap at the near-post, firing in a powerful low shot that smashed into the back of the net before Joe Lumley had even completed his dive.

Watford kicked on after going ahead, forcing a great deal of turnovers in possession and looking threatening every time they burst forward. However, Southampton’s threat remained, with the recalled Daniel Bachmann called into action for the first time to easily claim Carlos Alcaraz’s limp header.

Soon after, another free-kick in a dangerous position saw Lumley claim Wesley Hoedt’s effort, before he was equal to Jamal Lewis’ shot following a corner.

Lumley’s heart must have been in his mouth when Bayo got to a ball over the top before him, but the angle was too tight for the Ivorian to make the most of the empty net. Martins then burst forward and fed Asprilla, but an excellent last-ditch tackle from Taylor Harwood-Bellis prevented the Colombian from getting his shot away.

The Saints defender then found himself with a free header from a free-kick, but his effort went over the bar. Watford were just whiskers away from doubling their lead in first-half stoppage time when Bayo capitalised on a loose ball in the box, but his effort spun agonisingly wide of the far post.

Southampton started the first half the stronger of the two sides, with Alcaraz taking on a free-kick just outside the area, but his effort sailed over the bar. Asprilla then showed off his skill by getting past Holgate twice in quick succession, with Chakvetadze taking on a shot with the latter opening, forcing Lumley into a good save.

A period of end-to-end football ensued with both sides going close, but it was the Hornets who will feel they had the better opportunities. Ryan Andrews, excellent throughout, made a good interception and drove down the right before sending a cross-field pass to Sema, whose shot was blocked.

A late bombardment from a much-changed Saints line-up saw the Hornets under great pressure, which eventually was released when Armstrong picked up the ball on the edge of the area and smashed home beyond Bachmann’s reach to draw the sides level.

The Saints then pushed on for a winner, with fellow sub Sam Amo-Aweyaw cutting in before unleashing a dangerous curling strike on target that Bachmann did excellently to push wide.

Andrews had an opportunity to steal the win with seconds remaining when he burst through beyond the halfway line, but with little support, his shot from the right of the box was unable to challenge Lumley.

A draw means the two sides will do battle once again during week commencing Monday February 5, to see which of the teams will travel to either Liverpool or Norwich City in the fifth round.