Striker Matt Smith chose the perfect occasion to score his first goals at Boundary Park as his first-half double helped npower League One Oldham produce an FA Cup upset in beating Liverpool 3-2.
The 23-year-old, who 18 months ago was playing non-league football with Solihull Moors, had the best day of his fragmented professional career after giving the Reds' defence a torrid time.
He scored either side of Luis Suarez's 21st of the season in the first half before Reece Wabara's header put the Latics into the last 16 despite Joe Allen's goal 11 minutes from time. It was the first time Liverpool had been beaten away from home in the FA Cup by a team at least two divisions below them since defeat at non-league Worcester City in 1959.
Smith gave indication of his threat in just the third minute with the sort of goal you associate with a player of his physical stature. Youssouf M'Changama swung over a cross from the left and the 23-year-old used every inch of his 6ft 6in frame to out-muscle Sebastian Coates and head past Brad Jones.
Former Everton forward Jose Baxter did his best to make life difficult for the red half of Merseyside, twice shooting wide from distance, but it was Suarez who was next to feature and significantly so.
The Uruguay international, captaining the side, set off on a driving run from deep and looked to pass but got a lucky rebound off defender Cliff Byrne and reacted quickly to hammer the ball inside Dean Bouzanis' left-hand post. It was his fifth goal in six FA Cup appearances and his eighth strike in as many games.
His touch to Jordan Henderson's inswinging free-kick then diverted the ball into the net only to be denied by an offside flag. Raheem Sterling should have scored after Suarez's pass was backheeled into his path by Fabio Borini but he shot straight at the keeper.
But Oldham remained unbowed as they took great heart from the physical battles they were winning and were rewarded with a second goal moments before the interval.
Smith, who had already had a header tipped over by Jones in added time, converted the simplest of chances after a howler by the Liverpool goalkeeper, who fumbled Wabara's cross to allow Robbie Simpson to square a pass for the striker to poke home. Borini had the chance to equalise from Jack Robinson's cross with the second half less than a minute old but he side-footed over and it proved costly.
The visitors' defensive fallibility in the air was exposed again as Carl Winchester swung a cross to the far post and Wabara rose above Robinson to head over Jones into the far corner. Allen pulled one back with 11 minutes to go to with a shot which deflected in off Baxter but Oldham held on to reach the fifth round for the first time in 19 years.