As shock results go, Liverpool's humiliating 7-2 defeat by Aston Villa - a team who only avoided relegation on the final day of last season - must be right up there near the very top.
After looking almost superhuman for most of the previous campaign, Jurgen Klopp's players were handed a reality check of the highest order last Sunday night as Ollie Watkins and Co repeatedly tore through them to devastating effect.
Despite enjoying just 30 per cent possession, Villa managed 18 efforts at goal with 11 of those on target. It is no exaggeration to say they could've hit double figures.
Liverpool's players look dejected after Aston Villa scored their seventh goal on Sunday night
For Klopp - and in particular his usually rock solid defence - it was a reminder that this season will be tougher than last term's procession to the Premier League title.
But where did it all go wrong at Villa Park? And what does Klopp need to fix ahead of a huge Merseyside derby against leaders Everton after the international break?
Here, Sportsmail takes a closer look at the champions' weaknesses which were so ruthlessly exposed by Villa.
Reds goalkeeper Adrian looks on as a giant scoreboard at Villa Park displays the 7-2 scoreline
VAN DIJK LOSES HIS AIR OF INVINCIBILITY
Since arriving at Anfield in 2018, Virgil van Dijk has been Klopp's Mr Reliable, the one player who always puts in a solid - and more often than not, impressive - display, regardless of the opposition.
His incredible levels of consistency have led to him being widely regarded as the best central defender in the world - he finished second to Lionel Messi in last year's Ballon d'Or - and have helped Liverpool become the dominant force in English football.
But things have been different this season. After a sloppy period during Project Restart, an uncharacteristic mistake against Leeds on the opening day of the season allowed Patrick Bamford to score and prompted Jamie Carragher to brand the Dutchman 'arrogant'.
Wim Kieft, who won Euro 1988 with Holland, also called the former Southampton star 'lazy' and 'nonchalant' last month, words which would not look out of place in a description of his performance against Villa.
Van Dijk appeared rattled early on and struggled to get to grips with the movement of £28million man Watkins. Normally calm on the ball and when faced with onrushing attackers, he was anything but as Villa burst forward on the counter.
The fear factor he exuded last term has quickly disappeared. Klopp must hope he gets it back - and quick.
Virgil van Dijk had a game to forget as Villa repeatedly found a way through the Reds' defence
ADRIAN IS NO ALISSON
Liverpool would've lost with Manuel Neuer or Jan Oblak in goal on Sunday night, but the fact they were missing their No 1 at Villa Park certainly didn't help matters.
Alisson was ruled out after injuring his shoulder and in his place stepped Adrian, a goalkeeper with a history of high-profile errors during his short time on Merseyside.
The former West Ham shot-stopper was directly at fault for Watkins' opener after his poor pass went straight to Jack Grealish, while he could have done better with at least a couple of the other strikes which nestled in the back of his net.
With Alisson, one of the division's best keepers, ruled out for up to six weeks, Adrian represents a major downgrade in the goalkeeping department for a crucial period of the