Gabriel‘s own goal in the first half was enough to earn Southampton their first ever win over Arsenal in the FA Cup.
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.”
Southampton started brightly and James Ward-Prowse came close to scoring inside five minutes but his corner rattled the crossbar.
The hosts tooks a deserved lead after 24 minutes when Gabriel deflected in a low cross from Kyle Walker-Peters.
Arsenal improved in the second half and Rob Holding had a good chance to equalise from a corner but failed to hit the target.
Nketiah failed to score with a decent chance in stoppage time and Southampton held on. They will face Wolves in the fifth round of the FA Cup in February.