(Reuters) - Arsene Wenger said Arsenal's lack of urgency early in the match and not his team selection was to blame for the London club's 2-0 League Cup quarter-final loss to Southampton on Wednesday.
Southampton will take on Liverpool in the semi-finals after first half goals from Jordy Clasie and Ryan Bertrand got them past a weakened Arsenal side and into the last four for the first time since 1987.
"We didn't have enough urgency in the first half. We were weak in some departments and we paid for that," Wenger told reporters.
"We gave ourselves a mountain to climb. We were not good enough defensively and gave cheap goals away ... it was one of these nights where we looked like we could play for two hours without scoring a goal."
Wenger made 10 changes to his side from the team that beat Bournemouth last weekend but would not accept that as a reason for the defeat.
"I don't think the problem was there. We had players who are used to top-level competition, but I think we maybe didn't have the right urgency from the start," the 67-year-old added.
"We were not incisive enough in the first half, especially. In the second half they played very deep and were sharper than us."
Southampton manager Claude Puel made eight changes from the side that beat Everton at the weekend and, although impressed the victory, warned against complacency.
"We moved the team at the start with different players and the answer from them was fantastic," Puel told the club website. (www.southamptonfc.com)
"We will see for the future of the competition, but for now we have no time to be satisfied and happy because it's important ... to make a good result in the Premier League and then we have a very important final game in the Europa League."
Tenth-placed Southampton visit Crystal Palace in the league on Saturday before their Europa League match at home against Israeli side Hapoel Be'er Sheva.
Southampton will take on Liverpool over two legs in the League Cup semi-finals on Jan. 10 or 11 and Jan 24 or 25 to decide who plays Manchester United or Hull City in the final.
(Reporting by Debanjan Bose in Bengaluru)