Manager Brendan Rodgers was upset with Liverpool's young players after a shock FA Cup fourth-round defeat by Oldham.
The League One side beat the seven-times FA Cup winners 3-2 with striker Matt Smith scoring twice.
Rodgers said: "I was bitterly disappointed with the young players as they had a chance to compete for a club that has to challenge for trophies.
"We lost our concentration and only had spells in the last 35 minutes when we were at the right level."
He added: "The intensity of our game was nowhere near where it should be at the beginning. We gave the ball away too easily and were not strong enough physically.
"Congratulations to Oldham, though."
With Steven Gerrard on the substitutes bench, Liverpool were captained by Luis Suarez and Rodgers picked Daniel Sturridge, Fabio Borini and Raheem Sterling in attack ahead of midfielders Joe Allen and Jordan Henderson.
But former non-league striker Smith, 23, and fellow forward Robbie Simpson gave centre-backs Sebastian Coates and Martin Skrtel an uncomfortable afternoon.
Oldham are currently 19th in League One, just a point above the relegation zone, and their third-round win against Nottingham Forest was their only victory in their last nine games.
Smith scored either side of Luis Suarez's equaliser, with Reece Wabara heading another after half-time to put Paul Dickov's side 3-1 up.
And they defended resolutely as Liverpool fought back to score via a Joe Allen volley with 12 minutes remaining.
The defeat means that Liverpool's only chance of silverware in Rodgers's debut season is in the Europa League, with the Reds facing Russian side Zenit St Petersburg on 14 February.
"Matt Smith is a good player but we have played against that type before," added Rodgers.
"The FA Cup was a competition we wanted to have a go at and there is no excuse, we put out a strong team capable of winning the game but we didn't.
"There is no excuse. You have to take it on the chin, but there has been plenty of warnings throughout the weekend if your application is not right you can get found out."