The Reds were downed 2-1 by PSG at the Parc de Princes, extending their losing streak in Group C to three games. They now must beat Napoli at Anfield in two weeks time to qualify for the knockout rounds.
And Robertson says Liverpool were unable to control their frustration by PSG’s ‘play-acting’.
“I suppose they were in the lead and they were looking to waste time. You can use gamesmanship, play-acting, you can use it all really,” Robertson, who had words with Neymar, told Sky Sports.
“I would like to know how much time they wasted tonight. It’s frustrating when [Neymar] is falling like he is.
“It’s all part and parcel of his game and we needed to deal with that. We didn’t quite control our aggression.
“Of course it was frustrating. But when you play against PSG you know it is something you are going to come up against especially with him. It wasn’t something we quite dealt with tonight.”