Stevenage 1-4 Southampton
Southampton secured a comfortable passage into the League Cup third round with victory at Stevenage in the first ever meeting between the two clubs.
All the goals were scored in the second half, Premier League side Saints going 3-0 up via Tadanari Lee, Billy Sharp and Jason Puncheon's 30-yard volley.
Stevenage, unbeaten in League One this season, netted a late consolation through Michael Thalassitis.
But Southampton restored their three-goal lead through Ben Reeves.
Newly promoted Southampton have lost both of their opening games on their return to the Premier League and were looking for a morale-boosting win at the Lamex Stadium.
Saints boss Nigel Adkins fielded a completely different starting XI from Saturday's 2-0 home defeat by Wigan and they struggled to click in a goalless first half dominated by Stevenage.
Japan striker Lee, making his return from a five-month lay-off, made the home side pay when he calmly swept home Sharp's cross from 12 yards.
There was an element of controversy to the away team's second goal, with Sharp smashing in after referee Oliver Langford awarded a hotly disputed free-kick inside the Stevenage box.
Langford ruled that home defender Mark Roberts's mis-kick, picked up by goalkeeper Chris Day, was a deliberate backpass - much to the dismay of the hosts.
Puncheon wrapped up the win with a contender for goal of the round moments later. The winger picked up the ball 30 yards out and lifted it on to his knee before smashing a volley past the stranded Day.
Stevenage restored some pride in injury time when they pulled a goal back through substitute Thalassitis's 20-yard effort, before Southampton had the final say when Reeves struck brilliantly from the edge of the area.
Stevenage boss Gary Smith: "I'm not sure we got the rub of the green. The second goal was a pivotal moment in the game and if the referee shows a little more common sense he will see from Mark's body shape he is looking to play the ball across the pitch to the full-back.
"He touches the ball with his standing foot and his other foot touches it back to the keeper. Without that there could have been a different slant on the game.
"We played some very good football but the result looks like a bit of a beating. The second goal undoubtedly shook and rocked the players.
"I thought we lost out discipline and looked too open for a few minutes."
Southampton boss Nigel Adkins: "We knew it was going to be a tough test, but we have ticked a lot of boxes tonight.
"We scored four exceptional goals, Lee has scored and got 90 minutes under his belt after his injury and we showed exceptionally quick thinking for the second, and they were tremendous strikes from Jason and Ben."