Shane Long spared Southampton's blushes by bundling the Premier League side past Norwich in a last-gasp 1-0 win in Wednesday's FA Cup third round replay.
Norwich goalkeeper Michael McGovern parried the Republic of Ireland striker's last-ditch close-range header, only for Long to force the rebound home.
The underwhelming Saints struggled for rhythm all night, but finally squeezed past Championship outfit Norwich inside normal time, after the 2-2 draw at Carrow Road on January 7.
Southampton will now host Arsenal in the fourth round at St Mary's on Saturday, January 28.
Former Norwich forward Nathan Redmond spurned three fine second-half chances as this tie looked to be heading for extra-time, only for Long to produce his rescue act.