Jurgen Klopp's side now sit top of Group C on six points after thrashing Red Star Belgrade 4-0 in the reverse fixture at Anfield last month but the Reds boss knows it will be a much tougher task this evening in front of the hostile Marakana crowd.
"I do not say it is serious we lost two times, but of course we have to make sure that it will not happen again, otherwise it will be hard, because the next game is already an away game again, and then a tough home game".
However, defeat means they can not really afford to lose either of their two final round-robin matches against PSG and Napoli, who are both impressive sides.More news: Dez Bryant ready to sign with New Orleans Saints
And Robertson acknowledges that Liverpool are not at their best and need to work on finding fluency and rhythm in the final third.
'We will keep going and playing because it doesn't take much for those chances to go in'.
"Last season everyone was used to us scoring four or five goals", Robertson told British media. Liverpool's title challenge in 2014 under Brendan Rogers was aided by a lack of European football during an 11 game winning streak in the spring, bringing them closer to the title than they have ever been in the Premier League era. The boys are very disappointed, I'm very disappointed. We didn't start and when you don't start in the Champions League you get punished.More news: Jeff Sessions resigns as attorney general at Trump's request
But at the same time, Sadio Mane, Roberto Firmino and Mohamed Salah have been a level below their best as a trio - with Liverpool's attacking line again frustrating at Red Star, albeit with Sturridge starting in place of Firmino. That can't be possible every single game. This season we've found that a bit hard. It could yet be a moment that they look back on and see as a turning point in terms of giving them the shock they need to rediscover their best form, but supporters are right to be slightly concerned after what they saw in Belgrade tonight. But recent history suggests that exiting the Champions League at the group stage does not correspond with Premier League success towards the end of the season.
"We had chances to go in front. We have to do better".
Speaking of the Switzerland international's situation, the manager said, "We have heard and read the speculation and talk about what kind of reception Shaq would receive and although we have no idea what would happen, we want to go there and be focused 100 per cent on football and not have to think about anything else, that's all".More news: MI voters to decide on recreational marijuana, anti-gerrymandering, voting options
We know he changed the game at Salzburg when he came on, that was impressive that day.