Liverpool captain Jordan Henderson admitted they 'weren't happy' with referee Paul Tierney during their 0-0 draw with Manchester United.
Jurgen Klopp's side were unable to break down a resolute United defence at Anfield on Sunday as they endured their third successive match without scoring a goal.
However, they could have had a great chance to take the lead right on the stroke of half-time if Tierney didn't blow his whistle five seconds early into the one added minute from the first period.
Liverpool attacker Sadio Mane is played in behind the United defence from a long through ball, but the official blew his whistle moments before the pass was played, leaving the hosts baffled by the decision.