Liverpool missed the chance to extend their lead at the top of the Premier League as Danny Ings' stunning strike saw Southampton beat the champions 1-0 on Monday Night Football.
Former Reds striker Ings came back to haunt his old club with an exquisite, no-look lobbed finish inside two minutes at St Mary's which condemned Liverpool to their second defeat of the season and ended the champions' 12-game unbeaten run.
Southampton restricted Liverpool to just a single attempt on target as a resilient defensive display and commanding first Premier League clean sheet from goalkeeper Fraser Forster in over three years saw Ralph Hasenhuttl's side end a four-game winless run.
Liverpool remain top of the Premier League ahead of Manchester United on goal difference, but have played a game more and have now failed to win their last three games. Southampton, meanwhile, climb to sixth and are just four points adrift of the champions.
Southampton: Forster (7), Walker-Peters (8), Stephens (7), Bednarek (7), Bertrand (6), Ward-Prowse (7), Diallo (6), Armstrong (7), Djenepo (6), Ings (7), Walcott (7).
Subs: Tella (6), N’Lundulu (6), Valery (7).
Liverpool: Alisson (6), Alexander-Arnold (5), Fabinho (6), Henderson (6), Robertson (6), Wijnaldum (5), Thiago (5), Oxlade-Chamberlain (5), Salah (5), Firmino (6), Mane (6).
Subs: Shaqiri (5), Milner (6).
Man of the Match: Kyle Walker-Peters
How Ings and Saints haunted Liverpool
It took just two minutes for Southampton to take the lead with their very first attack of the game. James Ward-Prowse's flicked free-kick found its way through to Ings after Trent Alexander-Arnold misread the flight of the ball, and the Saints striker haunted his former club with a brilliant lobbed effort into the far corner over Alisson.
Liverpool's makeshift and shellshocked defence struggled to get to grips with the pace and movement of Southampton's attacking line, and they nearly fell two behind when Ings cushioned a cross into the path of Moussa Djenepo on 26 minutes, but he curled wide of the target.
Sadio Mane looked to spark an uncharacteristically tame Liverpool attacking display into life on 34 minutes, but having drifted in behind Kyle Walker-Peters, blazed wildly over the target.
Southampton lost Djenepo to injury but his replacement, Nathan Tella, nearly introduced himself style as he brilliantly capitalised on a slip from Fabinho to reach Ings' knockdown but flashed a shot inches wide.
With the half reaching an end, Liverpool finally shifted through the gears as Andy Robertson released Mane in behind, but having stood a teasing ball into the box, the finish was found wanting as Mohamed Salah steered a header onto the roof of the net.
- Fraser Forster made his first Southampton appearance since May 2019 as Ralph Hasenhuttl made three changes from the goalless draw with West Ham.
- Alex Oxlade-Chamberlain made his first Premier League start of the season, Thiago Alcantara made his second and Jordan Henderson started at centre-back as Liverpool made three changes from the goalless draw at Newcastle.
Having had just 15 touches in the opposition box and failed to register a single shot on target in the first half, Liverpool emerged for the second period with renewed intensity but, with a lead to protect, Southampton were dogged in defence.
Jack Stephens survived a VAR check for handball after a Georginio Wijnaldum shot was blocked behind off his arm, and the Saints defender was in the right place at the right time to deny Mane ramming in a close-range equaliser just before the hour.
There were 75 minutes on the clock when Liverpool registered their first attempt on target, but Mane's scuffed effort was comfortably saved by Forster as he closed in on a clean sheet in his first Southampton appearance in 18 months.
Southampton could have sealed the win six minutes from time when Alisson vacated his area and was beaten to the ball by substitute Yan Valery, but his effort didn't have the legs to reach the target as the Liverpool goalkeeper's blushes were spared.
But there was to be no salvation for Liverpool as Southampton held on for a victory that throws the title race wide open, and left manager Hasenhuttl in tears at the full-time whistle.
What the managers said…
Southampton manager Ralph Hasenhuttl: "I've never taken points against Jurgen so far, I think I started believing we could do it in the 92nd minute, not earlier. You never know, they are so strong in front, and you always think something can happen.
"The way we defended today was amazing, I think the effort the guys put in, everybody, was the key of winning. The mentality was maybe even better than against most of the teams.
"It's a perfect start to 2021. No one expected to take points against them today, we have 29, we're on our way and let's keep on going. It was an important step forward."
Liverpool manager Jurgen Klopp: "The slow start cost us, that made life massively difficult tonight. All these things can happen, we are human beings. As great as the set-piece was [for Ings' goal] we knew they could do it and the player there who was there missed the ball, and then the next one was a great finish. We could have defended it.
"With the situations we had, the possession we had, the way we played, we should have worked Fraser Forster much more. He should have had much more to do with the game but that's the situation we put ourselves in.
"This was a rather rusty moment; we have to admit that. You can only solve a problem if you know the problem, and we are not blind to our problems. We have to fight and play through this, it's up to us to change that."
Carra: Liverpool's worrying first rough patch
Sky Sports' Jamie Carragher:
"I didn't see that coming, I expected a reaction from Liverpool on the back of two really poor performances. We've just seen another one. Liverpool's away form this season is so poor.
"When it comes to chances created, they haven't looked like scoring, even tonight again. Did Forster have to make a good save, a big save? Did anyone miss a real chance where they had to score?
"That is a really big worry for Liverpool at the moment, in terms of what they are creating away from home. It's nowhere near enough.
"This Liverpool team is amazing but it's going through one of its first rough real patches it has been through in the past two seasons. The big worry is where are the goals and creation coming from, because it's been non-existent."
Opta stats - Saints topple champions again
- Southampton are the first team in Premier League history to beat all seven winners of the competition in the season after a title win.
- Liverpool have failed to score in back-to-back Premier League games for the first time since May 2018, having found the net in each of their 21 previous league games.
- Liverpool's first shot on target in this match came in the 75th minute courtesy of Sadio Mane - it's the Reds' longest wait for an attempt on target in a Premier League match since December 2015 (89th minute vs Newcastle).
- After having eight shots on target in their 7-0 victory over Crystal Palace, Liverpool have mustered just seven attempts on target across their last three Premier League matches.
- Southampton's James Ward-Prowse has provided four assists in the Premier League this season - only in 2014-15 (6) has he had more in a single top-flight campaign.
- Southampton keeper Fraser Forster kept his first Premier League clean sheet since October 2017 (1-0 vs West Bromwich Albion), though this was just his 13th appearance in the competition since then.
Man of the Match - Kyle Walker-Peters
Southampton host League One Shrewsbury Town in the third round of the FA Cup on Saturday at 8pm, before travelling to Leicester in the Premier League on January 16 at 8pm.
Liverpool head to Aston Villa in the third round of the FA Cup on Friday at 7.45pm, before hosting Manchester United on Super Sunday on January 17 - live on Sky Sports Premier League.