"Stand by for Operation Anfield exercise" came the message over the Tannoy after 26 minutes. If it was a coded call designed to rouse the home team after a subdued start, it did not work, and a gleeful Wigan Athletic took full advantage to claim their first- ever win at Liverpool.
Shaun Maloney's first-half penalty and captain Gary Caldwell's close-range finish after 63 minutes, sandwiching a Luis Suarez strike, secured a famous victory for the Lancashire club to revive their hopes of avoiding relegation, and leave their manager, Roberto Martinez, hailing his players. "It is a historic day for us," said the Spaniard. "Wigan Athletic beating Liverpool at Anfield – that is why we are involved in football, [to] defy the odds and the history."
Wigan have now lost just once in seven matches and climbed level on points with third-bottom QPR, but the story of this game was also about Liverpool after a day that intensified the spotlight on their failings in the Premier League this season. The Merseyside club have won the Carling Cup and booked a Wembley return in the FA Cup semi-finals, but this humbling reverse was their fifth defeat in six in the League and means they have taken just eight points from a possible 33 since the start of 2012.
It was the last thing that Kenny Dalglish would have wanted after the late capitulation at QPR on Wednesday, and the manager's excuse of tiredness is unlikely to appease the supporters who booed Liverpool off at the end. "We looked a wee bit tired, we had a lot of possession but gave away the ball quite a lot. If you play Sunday, Wednesday, Saturday, it is going to take its toll."
In the spring sunshine Liverpool were sluggish, and Wigan profited after 30 minutes. When Maloney blocked a Jordan Henderson clearance the ball span to Caldwell, who lifted it back into the Liverpool box, where Jamie Carragher's weak header presented an opportunity for Victor Moses. As he nodded goalwards, he was caught on the chin by a boot from Martin Skrtel and Lee Mason pointed to the spot.
Moses, who suffered cuts to his face and suspected concussion, required lengthy treatment, but Maloney held his nerve and steered his spot-kick low to Pepe Reina's right for his first goal since joining Wigan from Celtic last August.
Until then Liverpool's only threat of note had been a Stewart Downing effort that flashed just past the far post. They drew a couple of saves from Ali Al Habsi through Suarez and Steven Gerrard, but evidence of Liverpool's frustration came as Kenny Dalglish had a heated exchange with Martinez on the touchline.
Yet when Suarez levelled two minutes after the restart, playing in Gerrard down the right and tucking the ensuing cross past Al Habsi, it seemed likely Liverpool would go on and win the game. And they might have done had Suarez not been penalised for using his hand to turn the ball in on the line after Skrtel's back-post header had bounced over Al Habsi.
Dalglish argued that Suarez had used his shoulder and said that the referee had got the decision wrong. "There is no rhyme nor reason why the second goal should be chalked off," he said.
A reprieved Wigan regained the advantage when from a half-cleared free-kick James McCarthy drove the ball back into the Liverpool box and it deflected off Carragher to Caldwell, who finished like a centre-forward, sidestepping Andy Carroll and slipping the ball under Reina.
Martinez said of his captain: "I think he surprised the whole Anfield crowd and he surprised even our bench." Dave Whelan, Wigan's owner, was on his feet in the directors' box as the away fans sang: "We are staying up". Around the rest of Anfield there were only groans.
Liverpool (4-1-4-1): Reina; Flanagan, Carragher, Skrtel, Enrique; Spearing; Downing (Shelvey, 73), Henderson (Carroll, 46), Gerrard, Kuyt (Sterling, 84); Suarez.
Wigan ((3-4-3): Al Habsi; Alcaraz, Caldwell, Figueroa; Boyce, McCarthy, McArthur, Beausejour; Moses (Crusat, 42), Di Santo (Sammon, 82), Maloney.
Referee: Lee Mason.
Man of the match: Caldwell (Wigan)
Match rating: 7/10