Plymouth pulled off a stunning 1-0 fourth round win at Home Park this morning, ending the visitors' hopes of a quadruple.
The hosts took the lead in the 53rd minute after they were awarded a penalty for a handball by midfielder Harvey Elliott and Ryan Hardie stepped up to send Liverpool goalkeeper Caoimhin Kelleher the wrong way.
"We all came here today with a dream and we have done it. I don't know what to say," forward Hardie told ITV. "There is obviously a lot of pressure. It is about picking your side, and I committed to it," he said when asked about his penalty.
Premier League leaders Liverpool were bereft of ideas and had just one shot on target in the opening half, with Plymouth keeper Conor Hazard making a diving save in the 36th minute to keep out James McConnell's long-range shot.
Ahead of the Merseyside derby against Everton on Thursday morning (NZ time), Liverpool made wholesale changes with Mohamed Salah, Virgil van Dijk, Alisson Becker and Alexis Mac Allister among the big names rested and left at home.
Liverpool, who were also forced into an early change when defender Joe Gomez went down injured, failed to create many chances in a scrappy encounter as Plymouth, who sit bottom of the second-tier Championship, gradually grew in confidence.
Arne Slot's side switched gears after going down but Hazard proved to be the hero for Plymouth as the Northern Irishman brilliantly kept out Diogo Jota's volley in added time, as well as a header from Darwin Nunez.
"At the end of the day, it is my job. So I am delighted with that," Hazard said when asked about the Jota save.
NO QUADRUPLE
With Liverpool top of the Premier League, having strolled into the Champions League's last 16 and reached the League Cup final, some fans and pundits had begun to speculate about a potential quadruple.
Plymouth's remarkable victory, however, brought a shuddering halt to talk of a clean sweep of silverware for Slot's side, who had only lost three games all season, prior to this morning.
Having made 10 changes to the side that hammered Tottenham Hotspur 4-0 in the League Cup semifinal second leg at Anfield, Slot had no regrets over his team selection against Plymouth.
Nunez was the only established first-team player the Dutchman brought off the bench as Liverpool chased an equaliser at Plymouth, with the Uruguayan striker coming on in the 58th minute.
"(No regrets) because we've seen a few times already, it's a playing style that is difficult. I think today showed why we played with who we used, they need momentum to be ready for the upcoming months. We saw it today," Slot told reporters.
"The result is obvious, a big disappointment. Way we played, not a lot to be happy about. The boys kept fighting for 100 minutes. They kept fighting but credit to Plymouth, a good game-plan, worked hard and it was a clear penalty, correct decision."
Meanwhile, there was no surprise in the other FA Cup fourth-round tie with Premier League club Wolverhampton Wanderers beating Championship side Blackburn Rovers 2-0 at Ewood Park.
There was little to separate the two teams in the opening minutes before Wolves hit Blackburn with two rapid-fire goals through midfielder Joao Gomes in the 33rd minute and seconds later via forward Matheus Cunha.
Blackburn defender Dominic Hyam had the ball in the back of the net in the 19th minute but his celebrations were cut short when the linesman's flag went up for offside.
In the late game of the day Aston Villa beat struggling Tottenham Hotspur 2-1.
