London: Liverpool's poor first-half display against Premier League bottom side Swansea City left manager Juergen Klopp angry and frustrated as they lost 1-0 at the Liberty Stadium on Monday.
Klopp criticised his players for not sticking to their positions in the first half, allowing Swansea to score through defender Alfie Mawson five minutes before the break after a poor clearance by the club's record signing Virgil van Dijk.
"We lost the game in the first half, not only because we conceded the goal ... but we didn't keep the positions we wanted to be in. We wanted to do it differently, but it didn't work out," the German told Sky Sports.
"We're frustrated, of course, and I am frustrated and angry. That's because it's not necessary, what we did today," he added after his fourth-placed side failed to widen the two-point gap over Tottenham Hotspur in the race for Champions League spots.
Liverpool, unbeaten in 18 games in all competitions, started a four-game winning streak in the league by hammering the Swans 5-0 on December 26 but that ended after a defensive performance by the home side that required hard work and a little luck.
"We cannot get the points back. The boys did really well in the last few weeks, but that doesn't help us tonight. It still should feel really bad, and it feels bad," the German added.
Klopp's side dominated possession but with Swansea defending in numbers, the visitors had trouble finding a way through.
Liverpool forward Roberto Firmino almost equalised just before the final whistle but his header came back off the post, and Adam Lallana's shot on the rebound was deflected wide.
"The clearest chance we had was in the last second more or less - I don't know how that happened, how the ball is not in. A point would have been for sure OK, but not what we wanted before the game," Klopp said.