Substitute Mo Salah grabbed the fastest hat-trick in Champions League history as Liverpool thrashed Rangers 7-1 to complete a double over the beleaguered Light Blues.FULL MATCHH DETAILSJurgen Klopp's side had cantered to a 2-0 win over a tentative Gers side at Anfield last Tuesday but there was initially more fight about the Gers this time and they took the lead in the 17th minute with a Scott Arfield drive.Last season's finalists responded seven minutes later when Brazilian attacker Roberto Firmino headed in from a corner before grabbing a second in the 55th minute as the visitors' superior quality came to the fore.Striker Darwin Nunez added a third with a fine finish in the 66th minute before Salah grabbed three goals in six minutes and 12 seconds with Harvey Elliott notching as Giovanni van Bronckhorst's side crumbled.It was not so much a Battle of Britain as a massacre and the Govan side remain rooted at the bottom of Group A without a point.Liverpool are six points clear of Ajax and three behind leaders Napoli with two fixtures remaining.It was hoped by those of a Rangers persuasion that Ibrox could help fuel a much-needed positive result in their first Champions League campaign in 12 years and they were encouraged by Liverpool's injury woes.Luis Diaz, Joel Matip and Trent Alexander-Arnold were added to the list following Sunday's 3-2 loss to Arsenal, while Salah was dropped to the bench, along with Thiago and Diogo Jota, although the Egyptian would take the headlines later.Joe Gomez, Ibrahima Konate, Fabio Carvalho, Firmino, Elliott and Fabinho came into the side.Gers winger Ryan Kent took over from Rabbi Matondo on the left while Gers top scorer Antonio Colak was preferred to Alfredo Morelos, who started at