Steven Naismith scored an injury-time header to seal an FA Cup third-round replay for Norwich as they twice pegged Southampton back at Carrow Road.
Maya Yoshida's own headed goal had appeared to be enough for Saints to advance after Virgil van Dijk's volleyed opener was cancelled out by Steven Whittaker's penalty.
But the Canaries refused to lie down and Naismith met Whittaker's cross unmarked to secure a dramatic 2-2 draw, with both sides now in the hat for Monday's fourth-round draw.
Plenty of Norwich fans steered clear of the game, with the usually bustling Carrow Road down to a sparse attendance of 12,479.
Van Dijk returned from suspension to captain Saints, while want-away defender Jose Fonte was not even among the substitutes.
Only Yoshida, Dusan Tadic and James Ward-Prowse survived from the 3-0 Premier League defeat at Everton as Southampton boss Claude Puel stuck to his guns by rotating his squad.
Shane Long passed up an early opportunity to give the top-flight outfit the lead before Saints' 19-year old debutant goalkeeper Harry Lewis held a Martin Olsson free-kick.
After their slow start, Norwich started to enjoy the majority of possession, Jonny Howson having a shot deflected behind by Van Dijk with Lewis saving from Cameron Jerome's header soon after.
Michael McGovern had been recalled in the other goal and the Canaries stopper did well to push a Tadic free-kick behind after Alexander Tettey had fouled Long.
Referee Christopher Kavanagh decided not to book Lewis after he slid out of his box with the ball still in his grasp, but with nothing coming from the free-kick, it was Southampton who spurned a superb chance.
They countered at pace as Josh Sims freed Long, who burst through on goal before blazing well over the crossbar, with McGovern tipping the Republic of Ireland forward's next effort over as half-time approached.
But Saints would take the lead seconds later as the resulting corner was put over to the back post by Tadic at the second attempt and Van Dijk was unmarked to volley home.
Norwich were level just six minutes after the break courtesy of a moment of madness from Lewis, who took a heavy touch from a Van Dijk backpass and hauled Jerome to the ground as he chased the ball, conceding a penalty which Whittaker stroked home.
Southampton reacted well and dominated the next period of play, although they only had a Pierre-Emile Hojbjerg shot straight at McGovern to show for it.
Tadic stung the palms of McGovern with a drive from the edge of the box before Timm Klose was forced off the pitch to receive treatment on a knee problem, and with the Austrian on the sidelines, Saints re-established their lead as Yoshida nodded home Hojbjerg's cross.
The visitors looked to see the game out but failed to do so as, with four minutes added, Naismith scored his first goal since November when he guided Whittaker's centre past Lewis.