Trailing 3-0 from the first leg in the Nou Camp, Jurgen Klopp’s side cannot realistically afford to concede an away goal as that would require them to score a near-impossible five times.
Nevertheless, full-back Robertson stressed they were far from ready to give up without taking the fight to their opponents and results this season, the latest a late win at Newcastle, have proved this team never knows when they are beaten.
“We need a perfect game with a bit of luck because I think they will be thinking if they get a goal it kills the tie,” said the Scotland captain.
“We always believe but 3-0 against Barcelona is a bit different to scoring a late goal because you are starting three goals behind.
“We will fight for everything, we won’t give up and that’s all we can do.
“It will be a hell of a task but there is still hope and where there is hope there is still a way in.
“Special things happen at Anfield and we’re hoping for another special night. We’ll give 100 percent but we need a bit of luck as well.”
Anfield is famous for its European nights and Robertson is hoping for another boost from fans.
“It gives us a lift and it certainly has affected teams in the past,” he added.
“Barca are a different kettle of fish, I’m not sure it will affect them, but you saw last season it affected City when we beat them 3-0 [in their Champions League quarter-final], it affected Roma [who lost 5-2].
“Our home games have been really good so hopefully our fans will be at 100 per cent and hopefully we will be at 100 percent as well and we can react off that.”