Southampton have moved into fifth after Monday's 2-1 win over Brighton at the AMEX.
Saints went behind after 26 minutes when James Ward-Prowse's handball sent Pascal Gross to the penalty spot.
The German sent Alex McCarthy the wrong way to give Albion an early lead.
But Ralph Hasenhuttl's fought back despite being second best in the first-half, finding an equaliser through Jan Vestergaard's brilliant header.
The game look destined for a draw until Kyle Walker-Peters was fouled by Solly March.
The referee originally awarded a free-kick but a VAR check changed the decision to a penalty.
Danny Ings stepped up to the plate to fire in the winner for Southampton, who move above Manchester United into fifth place on the table with 20 points from 11 games.
