Is it tiredness? Is it nerves? Is it tactical naivety?
Southampton will play either Manchester United or Hull City in the League Cup final after beating Liverpool 1-0 in last night's semi-final second leg, for a 2-0 aggregate win.
It's the first time the Saints have reached the final of the tournament since 1979, and a chance at a first major trophy since their FA Cup triumph against Manchester United three years previously.
While Liverpool dominated possession, you could sense a Southampton goal all night. Claude Puel certainly did, unleashing Shane Long's pace on Liverpool's high defensive line on 45 minutes. And it was Long who finished the job in injury time.
The moment Shane Long sent #SaintsFC to Wembley! Reaction on SS1 now. https://t.co/yspEKtwsSP
— Sky Football âš½ï¸ (@SkyFootball) January 25, 2017
It was a night of enormous frustration for Liverpool. Roberto Firmino looked way off the pace. Daniel Sturridge lacked any sharpness when chances fell to him, and Emre Can felt the brunt of a lot of fans' frustrations on social media.
Jurgen Klopp's big problem though is that last night's performance isn't a once off.
The 1-0 win against Manchester City on New Year's Eve seemed like a statement victory, but since the clock turned into 2017, the momentum has halted.
Their only win in the last seven games was the 1-0 victory against Plymouth Argyle in the FA Cup third round replay, and they even needed a late Divock Origi penalty to avoid going to extra-time.
0 - The last time Liverpool failed to score in either leg of a semi-final was in the 1970/71 Fairs Cup v Leeds. Blank.
— OptaJoe (@OptaJoe) January 25, 2017
A draw against Manchester United wasn't a bad result, but when you add it to further draws against Sunderland and Plymouth, and a 3-2 defeat to Swansea it becomes part of a bigger problem.
Klopp's side need to get through the weekend's FA Cup fourth round game against Wolves unscathed, because when they return to Premier League action on January 31 they're welcoming Chelsea to Anfield.
That might just be a season-definer.
