Gerrard admits it was a job well done against the French side, but accepts there were perhaps too many nervy moments in the second period as Eric Geret's side chased an equaliser.
"It was nervy but it was a job well done," the skipper told liverpoolfc.tv. "We wanted the three points and a clean sheet and we got it. We lost control in the second half and there are a lot of things that need looking at.
"Marseille deserve credit because they were organised. We knew it would be difficult because they are fighting to stay in the competition. But we stuck together, defended well and hopefully in the next couple of days people will forget the second half performance and see that we have qualified.
"We know what we have to do in PSV on the last day. We have been there before and won so we have a lot of confidence. We want to win this group because I think it's important going into the last sixteen. There are no easy games in this competition, but if you want any kind of advantage then you want to win the group.
"We are good away from home in Europe and now we have to go and prove it again."