The 22-year-old tucked away in the 20th minute at St Mary's Stadium for the only goal of the game, ensuring that the Saints head to Merseyside in a fortnight's time sitting on a slender 1-0 advantage.
Redmond and his profligate teammates were unable to add to that scoreline against a poor Liverpool side, however, but the Englishman says that he will take solace from the fact they do at least have some sort of lead to protect.
"I should have scored four goals today," he told Sky Sports News. "I didn't realise how much time I had but I will learn from those mistakes. At least we won and we can take a lead to Anfield."
Southampton, who have not reached a major cup final in over a decade, face Burnley and Leicester City prior to the second leg at Anfield later this month.