Liverpool’s players endured a sleepless night in Istanbul after fireworks were set off outside their hotel, but it was the team’s second consecutive defeat that served as the real wake-up call.

The Premier League champions remain top of the table, so panic is hardly required, yet the vulnerabilities that have shadowed their early season were exposed once again in a 1-0 Champions League loss to Galatasaray.

Arne Slot, who made a seamless start after succeeding Jurgen Klopp and delivered the league title in his first season, has now encountered his first serious setbacks. Despite a summer outlay of nearly £450m, the campaign is beginning to resemble a transitional one rather than the smooth handover many anticipated.

Record signing Alexander Isak, who arrived from Newcastle for £125m, still lacks full match sharpness, while £116m addition Florian Wirtz from Bayer Leverkusen has so far struggled to adapt to Liverpool’s tempo.

Slot himself did little to help his cause in Istanbul. His bold decision to start Mohamed Salah on the bench backfired, with the hosts already ahead when the Egyptian was introduced just after the hour. Liverpool failed to generate meaningful chances, and the Dutch coach’s Midas touch deserted him on a night that felt unusually flat.

The last time Salah was benched in a Champions League tie was against Rangers in October 2022. It seems unlikely Slot will repeat that gamble anytime soon.

Liverpool, as they were when beaten at Crystal Palace and as they have been all season, were once again exposed by a Galatasaray side that had clearly done their homework well under coach Okan Buruk.

The warning signals were posted in the opening moments when Baris Alper Yilmaz did what other players have done too often for Slot's liking. The forward ran through on goal unchallenged, only for keeper Alisson to rescue Liverpool once more.

Slot used new right-back Jeremie Frimpong as a right-sided attacker, not exactly an act of faith in his defensive abilities, with recognised midfielder Dominik Szoboszlai moved to defence.

It was Szoboszlai who conceded the decisive 16th-minute penalty when he was adjudged to have fouled Yilmaz, Victor Osimhen completing the formalities amid scenes of near hysteria.

As former Scotland winger Pat Nevin so aptly put it on BBC Radio 5 Live: "It is so un-Liverpool."

After the loss at Selhurst Park, the trip to Istanbul was arguably the last thing Liverpool needed, walking into this hostile, fanatical atmosphere that is a ready-built stage for sporting theatre.

Galatasaray's fans gathered in their thousands in the bars and cafes close to this magnificent arena, built on a hill so it overlooks Istanbul, hours before kick-off.

And the cacophony inside also started hours before the start and, when the action began, every Liverpool touch was greeted with deafening, piercing whistles.

To add to Liverpool's misery on this miserable night in Turkey, the outstanding keeper Alisson went off injured in the 56th minute after another save from Osimhen, while in-form striker Hugo Ekitike also limped off later.