Arsenal had often bow out at this stage of the competition — this was their fifth quarter-final defeat from their last six and despite not making it a priority, Wenger still cut a frustrated and often angry figure on the touchline.
“We had a disappointing performance, especially in the first half when we have any cheap goals,” said Wenger.
“It was one of those nights when we looked like we could play for two hours without scoring a goal. We were weak defensively too. We were not incisive enough.”
This triumphant Southampton team, that also ended Arsenal’s 19-match unbeaten run in the process, was also full of different players, as Claude Puel made seven switches from the one that beat Everton at the weekend, was better in almost every area of the pitch.
They as good as won the game with first half goals from Jordy Clasie and Ryan Bertrand, but they could easily have won by more on a night that will have done Arsenal’s confidence no good as they prepare for a big weekend London derby at West Ham.
The Southampton players and fans, in a sold-out freezing Emirates Stadium, were more up for the task from the outset and it came as little surprise when they took a deserved 13th minute lead.
Bertrand started a break down the left and crossed low and hard. Tricky Moroccan Sofiane Boufal’s shot was blocked, but only as far as Clasie, who hit a first time right-foot rocket past Arsenal’s third choice keeper Emi Martinez.
Ireland’s Shane Long had a good chance on the break soon after and Arsenal midfielder Mohamed Elneny was booked for a foul that stopped another Bertrand as Arsenal looked rattled. Alex Iwobi had his name taken soon after as Wenger’s men betrayed their frustration at being unable to make any impression on a well-organised Southampton side.
Japanese defender Maya Yoshida was next into referee Kevin Friend’s book before proceeding to head the ensuing free-kick narrowly past his own post as Arsenal almost recorded an attempt on goal.
But they were still to trouble Southampton’s Fraser Forster before Puel’s men doubled their lead seven minutes before half-time.
The impressive Steven Davis was at the heart of the attack, playing in Boufal down the wing and he pulled the ball back for Bertrand to finish with a well-timed left foot shot from the edge of the area.
Arsenal lost Elneny soon after and they left the pitch for the interval to boos from sections of the home support and Southampton fans singing about going to Wembley.
“Elneny was sick before the game and had to come off with a bad stomach upset,” said Wenger.
Wenger looked furious and sent his men out with more purpose after the break and they had their first shots on goal, not that England keeper Fraser Forster needed to do any more than throw a glove on the less than convincing efforts from Lucas and Aaron Ramsey.
Substitute Granit Xhaka’s 30-yard free-kick effort was only marginally better.
Southampton, meanwhile, looked ever-dangerous on the break and Boufal so nearly scored their third.
Long had an even better chance to make the tie safe when he was put through with only Martinez to beat and man of the match Davis had an effort which looped on to the top of the Arsenal goal.
Wenger attempted to salvage something from the night by sending on Alex Oxlade-Chamberlain with half an hour to go, but the England man recorded only one attempt on goal.
Indeed, it was a Southampton substitute, Pierre-Emile Hojbjerg who went closer with a rasping right foot effort which was superbly saved by Martinez in the closing minutes.
By then, most of the 59,013 crowd had left to brave the delayed underground network while the Southampton supporters revved up their celebrations in style.
There was more jeering and booing at the sound of Friend’s final whistle but it was even more half-hearted than their team’s display.
Southampton went to celebrate in front of their fans as Arsenal seemed to scuttle off as quickly as possible.
Martinez 5; Jenkinson 5 (Maitland-Niles 64, ), Holding 6, Gabriel 5, Gibbs 6; Elneny 5 (Xhaka 43, ), Coquelin 6; Reine-Adelaide 5 (Oxlade-Chamberlain 62), Ramsey, Iwobi; Perez 4.
Forster; Martina, Yoshida, Van Dijk, Bertrand; Davis, Clasie, Reed 6 (Hojbjerg 64, 6), Boufal 7 (Sims 66, ), McQueen; Long.