Southampton progressed to the semi-finals of the EFL Cup for the first time since 1987 thanks to a convincing victory over a below-par and under-strength Arsenal. Goals from Jordy Clasie – his first for the club – and Ryan Bertrand secured victory for a Southampton side which inflicted a first defeat on the Gunners since the opening day of the season. Manager Arsene Wenger, who has never won this competition during his 20-year reign in north London, had made 10 changes to the Arsenal team which beat Bournemouth 3-1 in the Premier League on Sunday and paid the price. In Aaron Ramsey, Alex Iwobi and Mohamed Elneny, the Gunners had Premier League regulars in their starting line-up – but without Alexis Sanchez, Theo Walcott, Olivier Giroud and Mesut Ozil, they lacked guile and bite.

Southampton, who had only won once in their last 23 visits to Arsenal, deserved the victory and will play Liverpool in the two-legged semi-finals, with the first leg at St Mary’s in the week commencing 9 January. During his tenure as Arsenal manager, Wenger has regularly used this tournament to give games to those on the fringes of the first team. That perhaps explains why they have won only one of their last six quarter-finals in the competition. The majority of Wednesday’s starting line-up had defeated Nottingham Forest and Reading this season, but Southampton were a different prospect – a Premier League side with a game plan and nous. Arsenal’s £17m summer signing Lucas Perez started for the first time since the 2-0 win over Reading on 25 October, but was a peripheral figure as he and his team-mates lacked energy and urgency, especially in the first half.

Before the match, Wenger had said he hoped the victory over Bournemouth, which came following three successive league draws, would make his team more relaxed. But while the Gunners marginally improved after the break – the introduction of Alex Oxlade-Chamberlain adding pace – they rarely threatened. A long-distance strike from Ramsey and a second-half chance, which fell to Oxlade-Chamberlain, was as good as it got for them. Carl Jenkinson lost possession in his own half and the visitors pounced, with Steven Davis and Sofiane Boufal combining to set up Bertrand for a first-time shot from the edge of the box. Southampton could have scored a third, with Boufal and Pierre-Emile Hojbjerg going close, but so comfortable were the visitors that they never seemed in need of another goal.