​Who said the Carabao Cup was dead? 

Well, it was very much alive on Wednesday evening when Liverpool hosted Arsenal, a game that finished 5-5 with the Reds going through on penalties.

Liverpool v Arsenal - Carabao Cup Fourth Round

It was a breathtaking affair, end-to-end stuff made up of some sensational strikes and bizarre defending. Both sides had made wholesale changes to their starting lineup, making it no surprise that we saw an encounter with little continuity or grace. Instead, what we got was a frenzy of action, which ended with what most were expecting anyway - Liverpool heading to the quarter-finals.

But while this was somewhat of a free hit for Jurgen Klopp's ​Liverpool, alarm bells will be ringing for the German, who had to watch on as his youthful side shipped five goals. 

Now that doesn't happen too much for the reigning European champions, least of all at Anfield, where this was only the second time they had conceded five or more in a home game in 66 years. Yikes...

The last time the Kop had to witness their side let in this many was also against ​Ar​senal, in this very competition, a 6-3 defeat back in 2007 inspired by Julio Baptista, who bagged four.

Key defensive figures like Joe Gomez and ​James Milner played poorly on Wednesday evening, with the latter at fault for Arsenal's fourth. But, questions have been asked of Liverpool's first-choice back line all season. 

Ainsley Maitland-Niles,James Milner

The Reds have only kept two clean sheets from ten ​Premier League fixtures, having conceded a single goal in the other eight games. A defence which was so formidable last campaign, helping them to lofty heights, has looked a lot more vulnerable this time round and may prove costly for​ Liverpool further down the line.

Joel Matip's untimely injury will undoubtedly cause even more issues for Klopp, who has seemed relatively unconvinced of the qualities of both ​Dejan Lovren and Gomez. 

However, Liverpool's youthful look on Wednesday and Arsenal's remarkable hot-streak of finishing on the night should mean the problem isn't too much of a cause for concern.