Roberto Firmino scored in injury-time for Liverpool. © AFP Liverpool manager Jurgen Klopp is looking forward to a “really tough game” in the Club World Cup final against Flamengo after Roberto Firmino’s injury-time goal gave the Anfield side a hard-fought 2-1 win over Monterrey of Mexico on Wednesday. Firmino came off the bench to turn in a cross from fellow substitute Trent Alexander-Arnold in the 91st minute at the Khalifa International Stadium in Doha after Naby Keita’s early opener for a weakened Liverpool side had swiftly been cancelled out by Argentine striker Rogelio Funes Mori.Having taken time out from their seemingly relentless march towards the Premier League title to travel to Qatar, Liverpool will be relieved at coming through this test, and they remain on course to win this competition for the first time.However, they must now beat a Flamengo side who have won the Copa Libertadores and the Brazilian title in the last month under Portuguese coach Jorge Jesus, and who will have had an extra day to prepare for the final after defeating Saudi club Al-Hilal 3-1 on Tuesday.”Tough game, really tough game,” said Klopp when asked about the prospect of facing Flamengo in what will be a…