FA Cup holders Arsenal were dumped out of the competition in the fourth round after a 1-0 defeat at Southampton on Saturday.
Gabriel's own goal in the first half was enough to earn Southampton their first ever win over Arsenal in the FA Cup.
- Watch FA Cup LIVE on ESPN+ in the U.S.
The result brings an end to Arsenal's six match unbeaten in all competitions.
Before the match, Arsenal boss Mikel Arteta said captain Pierre-Emerick Aubameyang had traveled but was unavailable to play due to "personal reasons.