Liverpool's dreams of an 'Invincible' season were not just ended on Saturday, they were shattered in stunning fashion as relegation-threatened Watford stormed to a deserved 3-0 win at Vicarage Road.
It was a result which sent shockwaves around football - the biggest margin of victory for a team in the relegation zone against top of the table since 1985 - and Klopp may hope that it also sends shockwaves throughout his squad.
Liverpool have done an admirable job of avoiding complacency despite the destination of the Premier League title being all-but secured for some time now, but Saturday showed the first signs of it creeping in.
Klopp insisted that he did not see the result coming, but in truth Liverpool's performance level has dipped since the international break, with narrow wins over Norwich City and West Ham United as well as defeats to Atletico Madrid and now Watford.
However, it is important to keep the defeat in context and there will certainly be no overreaction from inside the Liverpool camp given that they still boast a 22-point lead at the top of the table and were on the joint-longest winning streak and second longest unbeaten run in English top-flight history going into the weekend.
Klopp always maintained that an unbeaten campaign was not the goal for Liverpool, but a treble-winning season will be and those hopes will be tested this month ahead of Tuesday's match and the Champions League last 16 second leg against Atletico Madrid.
Liverpool have worked their way through the FA Cup without giving many of their stars much game time so far, beating Everton in the third round before overcoming Shrewsbury Town via a replay - the second game of which was with their youngest ever starting lineup.
The Reds have not won this competition since the 'Steven Gerrard final' of 2006 and are already enjoying their best FA Cup run since 2014-15, and they are likely to field some of the more recognised first-team players for the trip to Stamford Bridge.
Both Klopp and the players themselves will demand a response to the Watford defeat whoever plays as they look to avoid falling to successive losses for the first time since January 2019.
If they are to bounce back immediately then they will need to rediscover their form at both ends of the field; they had only one shot on target at Vicarage Road and have now conceded five goals in their last two league games - as many as they had in their previous 14.
The Reds have conceded 11 goals in their past five domestic cup away games, though, and have lost their last two matches on the road across all competitions, which is as many defeats as they had suffered in their previous 20.
Chelsea's home record is not exactly formidable either, though, with the Blues having suffered eight defeats at Stamford Bridge this season - their highest tally since 1985-86.
The most recent of those was a particularly chastening 3-0 lesson at the hands of Bayern Munich in the Champions League last week, which was their heaviest ever home European defeat and their biggest in any competition since January 2018.
A visit from the world, European and soon-to-be English champions is arguably the last thing Frank Lampard's side need, then, although this is perhaps the most vulnerable the Reds have looked all season.
Chelsea are not best-placed to take advantage of that, though, having won just one of their last five games and two of their last eight.
Somehow the Blues have held on to fourth place throughout all that, but the chasing pack are closing in and Saturday's 2-2 draw with Bournemouth allowed Manchester United and Wolverhampton Wanderers to close that gap to three points.
Given their pre-season transfer ban, the loss of Eden Hazard and the relative inexperience of Lampard in the managerial stakes, a top-four finish would be regarded as a satisfactory season for Chelsea, and FA Cup glory would be a very welcome bonus on top of that.
It is a trophy Lampard won four times in the space of six seasons as a player, including victory over Liverpool in the 2012 final, but since he left the Blues they have won it just once more, doing so in 2017-18.
So far this season they have had a fairly straightforward route through to the fifth round with victories over Championship pair Nottingham Forest and Hull City, but Tuesday's match promises to be their toughest FA Cup test of the campaign yet.
Chelsea FA Cup form: WW
Chelsea form (all competitions): WDLWLD
Liverpool FA Cup form: WDW
Liverpool form (all competitions): WWWLWL
Uncertainty continues to surround the fitness of Tammy Abraham, who missed the draw with Bournemouth due to an ankle injury and has flown to Barcelona to consult a specialist regarding the problem.
Tuesday's match will also come too soon for N'Golo Kante, who continues to struggle with a muscle injury but could be ready in time for the weekend.
Callum Hudson-Odoi may be held back for the weekend too, while Christian Pulisic remains sidelined for the hosts and Andreas Christensen picked up a "small knock" against Bournemouth which is likely to keep him out.
Liverpool, meanwhile, will have Joe Gomez back available after the centre-back missed the Watford defeat with a slight knock.
Gomez's involvement could depend on the level of Klopp's rotation, though, having used the FA Cup to hand opportunities to young players so far this season.
Chelsea possible starting lineup:
Kepa; Azpilicueta, Tomori, Zouma; James, Jorginho, Barkley, Alonso; Willian, Batshuayi, Pedro
Liverpool possible starting lineup:
Adrian; N Williams, Matip, Lovren, Robertson; Milner, Fabinho, Jones; Oxlade-Chamberlain, Minamino, Origi
Head To Head
Tuesday's match will be the 11th FA Cup meeting between these two sides, with Chelsea currently leading the head-to-head record with six wins to four.
In all competitions Liverpool have lost just two of the last 12 meetings and have won each of their last three - their best run since a four-game winning streak from November 2010 to November 2011.
We say: Chelsea 1-1 Liverpool (Liverpool win on penalties)
These two sides went all the way to a penalty shootout when they met in the UEFA Super Cup in Istanbul earlier this season, and this could be a similarly tight contest. Liverpool are likely to be much-changed but will demand a response to Saturday's defeat, whereas Chelsea could field something closer to their first-choice XI but go into the game in poor form.
With replays no longer in effect from the fifth-round stage, we can see this one going all the way and Liverpool coming out on top in a shootout.
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