"Sadio, I am happy for you but, on the other hand, I could really kick you in the... lower back!" the German joked.
Klopp's desire to have Mane return from Gabon as quickly as possible was understandable, as Liverpool struggled terribly without their star summer signing from Southampton - and the very real fear is that their Champions League hopes are set to go up in smoke now that the 24-year-old has been officially ruled out for the rest of the Premier League season through injury.
It was the news that all Liverpool fans were dreading from the moment Mane was left writhing on the turf in agony after jarring his knee in an awkward collision with Everton defender Leighton Baines in last Saturday's 3-1 victory over their city rivals.
Indeed, while many had initially questioned the decision to pay £34 million for an exciting but inconsistent attacking talent, Mane's importance to Liverpool quickly became evident.
He marked his debut with a stunning strike in the opening-day win at Arsenal, leaving Calum Chambers for dead with a blistering turn of pace before cutting inside Nacho Monreal and firing an unstoppable shot past David Ospina.
He then missed the following weekend's trip to Burnley with a shoulder problem. Liverpool lost 2-0 - despite having 71.6 per cent possession. Without Mane, they simply had no cutting edge.
It has happened time and time again since. Indeed, the stats are as telling as they are damning.
With Mane in the starting line-up, Liverpool have won 19 of their 29 matches in all competitions, losing just three times.
By contrast, they have triumphed just three times in 12 outings without him in the first 11, with all three of those victories coming against weak opposition in cup competition: League Two outfit Plymouth Argyle, Championship side Leeds and an under-strength Spurs.
Five out of the other eight matches ended in defeat and his absence was most painfully felt in the two-legged loss to his former club Southampton in the semi-finals of the League Cup.
That was a hammer blow to Liverpool's hopes of winning a first trophy under Klopp but the target has always been Champions League football and that is now in serious jeopardy due to Mane's injury.
Indeed, Liverpool have played five Premier League games without him in the starting line-up and failed to win one, with Wednesday's 2-2 draw with Bournemouth the latest disappointment. Furthermore, their goals average drops from 2.3 to 1.2 when their leading marksman (13) is unavailable, while their points-per-game ratio drops from 2.1 to 0.5.
There is now the distinct possibility that they will now blow a glorious opportunity to secure a return to the Champions League.
Mane has proven a man for the big occasions this term, netting twice against both Arsenal and Tottenham in the league, as well as in both Merseyside derbies.
There have also been goals, though, against the likes of Leicester, Hull, West Brom, Watford and Sunderland, underlining that, while his pace is key to Liverpool picking off quality sides on the counter-attack, it is just as important to getting in behind packed defences.
Indeed, it is worth noting that not only is Mane the Merseysiders' leading league goalscorer - no other player has yet reached double figures this term - he has also completed more dribbles (68) than all of his team-mates.
Given Adam Lallana is also out injured at the moment, the Reds now head into the home stretch without two of the players most pivotal to their attacking game plan.
Liverpool currently sit third in the table and the highest-ranked team they have left to face in their eight remaining Premier League games is eighth-placed West Brom.
However, as has already been well-documented, it is against lower-table opposition that the Reds struggle. They afforded Bournemouth just two shots on target at Anfield in midweek. Both went in and two precious points were thrown away, meaning Manchester City, Manchester United and even Arsenal are all back within striking distance in the battle for a top-four place.
It is clear that given just how unreliable Liverpool's backline remains, attack is still the best form of defence for Klopp's side. Now, though, the German hasn't just lost his most reliable source of goals, he's also been robbed of his most influential forward.
In terms of Liverpool's Champions League prospects, Mane's season-ending injury is a terrible kick in the... lower back.