In at least one respect Adam Lallana has not changed. The England international is still a match-winner for Southampton. At the end of a week when he complained about a perceived insult from referee Mark Clattenburg, the 25-year-old was again the toast of his club's supporters as he came off the bench to secure victory in this thrillingly helter-skelter tie.
For a while it seemed the match would be governed by the Law of the Ex, as two Southampton-bred forwards scored for Burnley before a Burnley-born one scored for Southampton. Then Lallana, who has never left the club where he was reared, made his spectacular impact to secure the Premier League side's passage to the next round. But it was a close-run thing.
Burnley are second in the Championship and showed why they are pushing for a return to the top flight by playing some slick football and frequently worrying their hosts, who had made five personnel changes from their last league outing but still deployed a strong side.
Scott Arfield almost gave the visitors the lead after 47 seconds but his delicious curling effort missed the target by inches. Southampton scored against the run of play in the 22nd minute, when Nathaniel Clyne collected a pass from Steven Davis and rocketed a half-volley into the net from 20 yards. It was a spectacular way for the right-back to mark his first start after a month out with injury – and also to remind Roy Hodgson of the array of English talent blossoming at St Mary's.
Six minutes later Rickie Lambert made a similar point in equally flamboyant fashion. Again the last pass came from Davis but again calling it an assist seems generous, as the striker had much to do, namely arrow the ball into the top corner from outside the area.
Lambert should have secured victory moments later but shot over from 15 yards. Shortly afterwards he hobbled off with a dead leg and was replaced by Jay Rodriguez, the Burnley native signed from his boyhood club in 2012.
Burnley's manager, Sean Dyche, revived his side during the break and they injected new life into the tie in the 51st minute, when Sam Vokes met a cross from Dean Marney and guided a header into the bottom corner from 10 yards.
Five minutes later Burnley drew level. Danny Ings, released by Southampton as a youngster, bounded into the box and past the lumbering Jos Hooiveld before firing past Kelvin Davis at the near post. Game well and truly back on.
Davis atoned two minutes later when he showed lightning reflexes and a strong hand to tip away another Ings effort. Rodriguez fluffed a chance to put Southampton back in front in the 62nd minute, shooting weakly at Heaton, but he finished emphatically four minutes later. As several players paused after James Ward-Prowse fell in the box under a tackle, Rodriguez lashed the breaking ball into then net from 15 yards.
Still Burnley would not bow to the established order. They came within inches of equalising again when another piercing move led to Ings thrashing a low shot against the post. Mauricio Pochettino felt obliged to introduce Lallana and the midfielder was quick to make a decisive impact, cracking a low drive past Tom Heaton from 25 yards. It was just as well that he did, because Burnley scored again in the 86th minute, Kevin Long stabbing into the net after a Junior Stanislas corner.
"If there is a such a thing as losing a game the right way, then that is it," said Dyche. "Three of their scorers are England players and the right-back is £2.5m worth so that is a measure of the two clubs. But performance-wise we were excellent. We played with no fear, very good football and very good attack-minded. I think their players came off thinking wow, we could easily have got turned over."