Arne Slot was rightly frustrated with Liverpool’s approach to defending set-pieces, after conceding from a corner and a throw-in to lose 2-1 at Crystal Palace.Slot went into Saturday’s trip to Selhurst Park knowing Palace were defensively strong and particularly adept at attacking set-pieces.He set his side up in a questionable 4-2-2-2 formation from the off, which changed to a more orthodox 4-2-3-1 at half-time with Liverpool 1-0 down and struggling to break Palace down.Their biggest concern, however, came when facing set-pieces; Ismaila Sarr opened the scoring from a Daicha Kamada corner before Eddie Nketiah won it at the very end following Chris Richards’ long throw.“If you want to compete you need a very positive balance with set-pieces and even more so in this league,” Slot told Sky Sports.“It was one of our biggest strengths last season, now we have conceded two against Newcastle and two here.“But this league is more and more and more about set-pieces.”Nketiah’s winner was particularly frustrating for a number of reasons, not least that it was avoidable as Milos Kerkez conceded the set-piece due to his inability to clear with his right foot.Liverpool could not deal with the chaos Richards’ arrowed throw caused, and the ball fell to the former Arsenal striker to finish.“It is never ideal when you concede in extra time of extra time, but there was a sub so half a minute extra was fair,” Slot explained, avoiding any rhetoric over additional time.“I have to check when they exactly scored, but we have to defend the throw-in better.“We take learnings from all the games we have played and we can take even more from a game like this.”In many ways this defeat had been telegraphed, with Liverpool riding their luck more often than not in a previously unbeaten start to the campaign.The onus falls on set-piece coach Aaron Briggs to continue working on their setup in defensive situations, with Slot’s comment that it is an area the Premier League is “more and more and more about” ringing true.Palace will not be the last side Liverpool face who employ long throws and cleverly devised, physically dominant corner routines.Next time they will need to be better prepared to deal with them, as with Virgil van Dijk (6’5″), Ibrahima Konate (6’4″), Dominik Szoboszlai (6’1″), Ryan Gravenberch (6’3″) and Alexander Isak (6’4″) all starting they weren’t without the height required.