Liverpool got 2021 off to the worst possible start as they slumped to a 1-0 defeat at Southampton.

Despite entering the New Year top of the table, there's been a feeling the Reds haven't been at full capacity in recent weeks.

Aside from the resounding 7-0 win over Crystal Palace, draws with Fulham, West Brom and Newcastle have given Jurgen Klopp serious food for thought about his misfiring attack.

Nevertheless, Danny Ings' goal in the second minute, a brilliant chip from James Ward-Prowse's free-kick, meant that the champions would have to go on the front foot at St Mary's.

Liverpool laboured, but they didn't have a shot on target until the 75th minute when Sadio Mane finally tested Fraser Forster.

It simply wasn't the visitors' night and they are now in serious danger of being knocked off their perch again by a familiar foe. 

Having squandered the advantage to expand their lead at the summit, Liverpool could now be overtaken by Manchester United in the next Premier League gameweek. 

The Red Devils, of course, closed the gap with a 2-1 win over Aston Villa last time out, Paul Pogba winning a contentious penalty which was converted by Bruno Fernandes. 

And oh how Liverpool could have done with some spot-kicks of their own on the South Coast. 

Jack Stephens handled as he blocked a shot from Gini Wijnaldum and Mane was later felled inside the box. 

Klopp was his usual cheery self after a Liverpool setback - we're joking, of course - but he couldn't help but feel his side had been thwarted. And he couldn't help but bring up United's record, either. 

"What [referee] Andre Marriner did with Sadio Mane tonight, I'm not sure that's okay. Manchester United had more penalties in two years than me in five and a half years - but [we have] no excuses for tonight," he said, via James Pearce .

"It looked like a clear penalty. I turned around to the 4th official and asked if it would be checked. He said: 'We've checked it already, no pen.'"

United have had just one more penalty than Liverpool this season (data via Transfermarkt), but they have had 20 since the start of last season to the Reds' 10. 

During Klopp's reign, United have now had 42 penalties to Livrerpool's 30. 

The German also rued his side's overall display but praised the Saints' work ethic. 

"Very frustrating because it was so unnecessary," he added.

"Our decision making was not good, it was the last pass. Our fault, my responsibility.

"Of course we worry. We are not silly. We have to show a reaction 100%. Southampton deserved it. They ran their socks off."